Method and device for transmitting data

ABSTRACT

A method and device for transmitting data are provided. The method includes: determining, after receiving a first message sent by a user equipment, whether first indication information is set, where the first indication information indicates that a server buffers downlink data to be sent to the user equipment; and when determining that the first indication information is set, retaining a signaling connection to the user equipment, and triggering the server that buffers the downlink data to send the downlink data to the user equipment. The method and device for transmitting data according to the embodiments of the present invention can save power of a user equipment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/577,259, filed on Dec. 19, 2014, which is a continuation ofInternational Patent Application No. PCT/CN2013/082329, filed on Aug.27, 2013. The International Application claims priority to ChinesePatent Application No. 201210307890.1, filed on Aug. 27, 2012 andChinese Patent Application No. 201210346533.6, filed on Sep. 18, 2012.All of the afore-mentioned patent applications are hereby incorporatedby reference in their entireties.

TECHNICAL FIELD

Embodiments of the present invention relate to the communications field,and more specifically, relate to a method and device for transmittingdata, where the device for transmitting data includes a core networkcontrol entity, a user equipment, and a server.

BACKGROUND

With the development of communications technologies, reducing powerconsumption of communications devices is becoming increasinglyimportant. In the conventional art, there is a power saving solution fora user equipment, where the solution provides a condition for triggeringa server to send downlink data to a user equipment in a scenario inwhich the server sends data to the user equipment, thereby achieving aneffect of saving power of the user equipment. A specific process is asfollows:

The user equipment initiates a tracking area update (TAU)/routing areaupdate (RAU) request and starts to execute a TAU/RAU process; afterreceiving the TAU/RAU request, a core network control entity (forexample, a mobility management entity (MME) or a serving general packetradio service support node (SGSN)) indicates to the server (for example,a services capability server (SCS) or a machine type communication (MTC)server) that the user equipment has sent the TAU/RAU request andinstructs the server to send buffered downlink data to the userequipment; and the server sends the buffered downlink data to the userequipment according to the instruction of the core network controlentity.

However, in this solution, each time receiving a TAU/RAU request sent bya user equipment (for example, an MTC device), a core network controlentity needs to notify a server; and apparently, regardless of whetherthe server has downlink data to be sent to the user equipment, the userequipment needs to enable a receiver or a wireless module to wait forthe downlink data of the server. Therefore, if the server has no data tobe sent to the user equipment, time for the user equipment to wait iswasted. Especially for a user equipment that sends a TAU/RAU messagefrequently, waiting for multiple times is extremely adverse to powersaving for the user equipment.

SUMMARY

Embodiments of the present invention provide a method, core networkcontrol entity, user equipment, and server for transmitting data, whichcan achieve an effect of saving power of a user equipment.

According to a first aspect, a method for transmitting data is provided,including:

determining, after receiving a first message sent by a user equipment,whether first indication information is set, where the first indicationinformation indicates that a server buffers downlink data to be sent tothe user equipment; and

when determining that the first indication information is set, retaininga signaling connection to the user equipment, and triggering the serverthat buffers the downlink data to send the downlink data to the userequipment.

With reference to the first aspect, in a first possible implementationmanner of the first aspect, the triggering the server that buffers thedownlink data to send the downlink data to the user equipment includes:

sending a downlink data delivery request message to the server thatbuffers the downlink data, so as to trigger the server that buffers thedownlink data to send the downlink data to the user equipment; orincludes:

sending a first user equipment reachability notification message to ahome subscriber server or home location register to which the userequipment belongs, so that the home subscriber server or the homelocation register sends a second user equipment reachabilitynotification message to the server that buffers the downlink data, so asto trigger the server that buffers the downlink data to send thedownlink data to the user equipment.

With reference to the first aspect or the first possible implementationmanner of the first aspect, in a second possible implementation mannerof the first aspect, the retaining a signaling connection to the userequipment includes:

sending a second message including second indication information to theuser equipment, where the second indication information indicates thatthere is data to be sent to the user equipment, so as to retain thesignaling connection to the user equipment.

With reference to the second possible implementation manner of the firstaspect, in a third possible implementation manner of the first aspect,the sending a second message including second indication information tothe user equipment includes:

when duration, preset for the user equipment, in which a signalingconnection can be retained is less than a predetermined threshold,sending the second message to the user equipment.

With reference to the first possible implementation manner of the firstaspect, the second possible implementation manner of the first aspect,or the third possible implementation manner of the first aspect, in afourth possible implementation manner of the first aspect, the methodfurther includes:

when determining that the first indication information is not set,sending a third message including third indication information to theuser equipment, where the third indication information indicates thatthere is no downlink data to be sent to the user equipment, so that theuser equipment disables a receiver or enters a power saving mode orshuts down according to the third indication information.

With reference to the second possible implementation manner of the firstaspect or the third possible implementation manner of the first aspect,in a fifth possible implementation manner of the first aspect, thesecond indication information further includes address information ofthe server.

With reference to the first possible implementation manner of the firstaspect, the second possible implementation manner of the first aspect,the third possible implementation manner of the first aspect, the fourthpossible implementation manner of the first aspect, or the fifthpossible implementation manner of the first aspect, in a sixth possibleimplementation manner of the first aspect, before the determining, afterreceiving a first message sent by a user equipment, whether firstindication information is set, the method further includes:

when the user equipment is a time-controlled user equipment, determiningwhether the current time is within a range of allowed communicationtime, where

the determining whether first indication information is set includes:

when determining that the current time is within the range of allowedcommunication time of the user equipment, determining whether the firstindication information is set.

With reference to the first possible implementation manner of the firstaspect, the second possible implementation manner of the first aspect,the third possible implementation manner of the first aspect, the fourthpossible implementation manner of the first aspect, the fifth possibleimplementation manner of the first aspect or the sixth possibleimplementation manner of the first aspect, in a seventh possibleimplementation manner of the first aspect, before the determiningwhether first indication information is set, the method furtherincludes:

receiving a second user equipment reachability notification requestmessage that is sent by the home subscriber server or home locationregister to which the user equipment belongs after the home subscriberserver or home location register receives a first user equipmentreachability notification request message, and setting the firstindication information according to the second user equipmentreachability notification request message; or

receiving data buffering indication information sent by the server thatbuffers the downlink data, where the data buffering indicationinformation indicates that the server buffers the downlink data to besent to the user equipment, and setting the first indication informationaccording to the data buffering indication information.

With reference to the first possible implementation manner of the firstaspect, the second possible implementation manner of the first aspect,the third possible implementation manner of the first aspect, the fourthpossible implementation manner of the first aspect, the fifth possibleimplementation manner of the first aspect or the sixth possibleimplementation manner of the first aspect, in an eighth possibleimplementation manner of the first aspect, before the determiningwhether first indication information is set, the method furtherincludes:

receiving a context response message sent by a source core networkcontrol entity serving the user equipment; and

when the context response message includes the first indicationinformation, setting the first indication information.

With reference to the first possible implementation manner of the firstaspect, the second possible implementation manner of the first aspect,the third possible implementation manner of the first aspect, the fourthpossible implementation manner of the first aspect, the fifth possibleimplementation manner of the first aspect, the sixth possibleimplementation manner of the first aspect, the seventh possibleimplementation manner of the first aspect or the eighth possibleimplementation manner of the first aspect, in a ninth possibleimplementation manner of the first aspect, before the determining, afterreceiving a first message sent by a user equipment, whether firstindication information is set, the method further includes:

when determining, according to the first indication information, that avalidity period of the downlink data expires, deleting the firstindication information, where the first indication information isfurther used to indicate the validity period of the downlink data, andthe validity period, indicated by the first indication information, ofthe downlink data is set according to a validity period, of the downlinkdata, carried in the data buffering indication information sent by theserver that buffers the downlink data; or includes:

receiving a fourth message that is sent, after a validity period of thedownlink data expires, by the server that buffers the downlink data,where the fourth message is used as an instruction to delete the firstindication information, and deleting the first indication informationaccording to the fourth message; or includes:

receiving a first user equipment reachability notification cancellationmessage sent by the home subscriber server or home location register towhich the user equipment belongs, and deleting the first indicationinformation according to the first user equipment reachabilitynotification cancellation message.

With reference to the ninth possible implementation manner of the firstaspect, in a tenth possible implementation manner of the first aspect,the receiving a first user equipment reachability notificationcancellation message sent by the home subscriber server or home locationregister to which the user equipment belongs includes:

receiving the first user equipment reachability notificationcancellation message that is sent by the home subscriber server or thehome location register according to a second user equipment reachabilitynotification cancellation message sent by the server that buffers thedownlink data of the user equipment; or includes:

receiving the first user equipment reachability notificationcancellation message that is sent by the home subscriber server or thehome location register after the home subscriber server or the homelocation register determines, according to the first user equipmentreachability notification request message, that the downlink dataexpires, where the first user equipment reachability notificationrequest message carries the validity period of the downlink data.

With reference to the second possible implementation manner of the firstaspect or the third possible implementation manner of the first aspect,in an eleventh possible implementation manner of the first aspect, themethod further includes:

after receiving a downlink data notification message or downlink datasent by the server that buffers the downlink data, establishing anevolved universal terrestrial radio access network radio access bearercorresponding to a bearer for transmitting a corresponding data packetor establishing a radio access bearer corresponding to a Packet DataProtocol context for transmitting a corresponding data packet; or

establishing a user plane bearer or a Packet Data Protocol context.

According to a second aspect, a method for transmitting data isprovided, including:

sending a first message to a core network control entity; and

when receiving a third message that includes third indicationinformation and is sent by the core network control entity according tothe first message, disabling a receiver or entering a power saving modeor shutting down, where the third indication information indicates thata server has no downlink data to be sent to a user equipment.

With reference to the second aspect, in a first possible implementationmanner of the second aspect, the method further includes:

when receiving a second message that includes second indicationinformation and is sent by the core network control entity according tothe first message, retaining an established signaling connection, so asto wait to receive downlink data, where the second indicationinformation indicates that the server has downlink data to be sent tothe user equipment.

With reference to the second aspect or the first possible implementationmanner of the second aspect, in a second possible implementation mannerof the second aspect, when the method includes the retaining, whenreceiving a second message that includes second indication informationand is sent by the core network control entity according to the firstmessage, an established signaling connection, the method furtherincludes:

when a current access network is a general packet radio servicetechnology network, determining whether a Packet Data Protocol contextis reserved; and

when no Packet Data Protocol context is reserved, initiating a PacketData Protocol context process, so as to establish a Packet Data Protocolcontext.

According to a third aspect, a method for transmitting data is provided,including:

sending a first user equipment reachability notification request messageto a home subscriber server or home location register to which a userequipment belongs, so that the home subscriber server or the homelocation register sends a second user equipment reachabilitynotification request message to a core network control entity to whichthe user equipment belongs, and therefore the core network controlentity sets first indication information according to the second userequipment reachability notification request message, where the firstindication information indicates that a server buffers downlink data tobe sent to the user equipment, and the server sends the downlink data tothe user equipment when receiving a second user equipment reachabilitynotification message that is sent by the home subscriber server or thehome location register after the home subscriber server or the homelocation register receives a first user equipment reachabilitynotification message that is sent by the core network control entityaccording to the first indication information; or

sending data buffering indication information to a core network controlentity to which a user equipment belongs, so that the core networkcontrol entity sets first indication information according to the databuffering indication information, where the data buffering indicationinformation indicates that a server buffers downlink data to be sent tothe user equipment and the first indication information indicates thatthe server buffers the downlink data to be sent to the user equipment,and the server sends the downlink data to the user equipment whenreceiving a downlink data delivery request message that is sent by thecore network control entity according to the first indicationinformation.

With reference to the third aspect, in a first possible implementationmanner of the third aspect, when the method includes the sending a firstuser equipment reachability notification request message to a homesubscriber server or home location register,

the method further includes: when determining that the downlink dataexpires, sending a second user equipment reachability notificationcancellation message to the home subscriber server or the home locationregister, so that the home subscriber server or the home locationregister sends a first user equipment reachability notificationcancellation message to the core network control entity, and thereforethe core network control entity deletes the first indication informationaccording to the first user equipment reachability notificationcancellation message; or

the first user equipment reachability notification request messagefurther includes a validity period of the downlink data, so that thehome subscriber server sends a first user equipment reachabilitynotification cancellation message to the core network control entitywhen determining, according to the first user equipment reachabilitynotification request message, that the validity period of the downlinkdata expires, and therefore the core network control entity deletes thefirst indication information according to the first user equipmentreachability notification cancellation message.

With reference to the third aspect, in a second possible implementationmanner of the third aspect, when the method includes the sending databuffering indication information to a core network control entity,

the method further includes: when determining that a validity period ofthe downlink data expires, sending a fourth message to the core networkcontrol entity, where the fourth message is used to instruct the corenetwork control entity to delete the first indication information; or

the data buffering indication information further includes a validityperiod of the downlink data, so that the core network control entitysets the first indication information that is further used to indicatethe validity period of the downlink data, and deletes the firstindication information when the validity period of the downlink dataexpires.

According to a fourth aspect, a core network control entity is provided,including:

a first determining unit, configured to: after receiving a first messagesent by a user equipment, determine whether first indication informationis set, where the first indication information indicates that a serverbuffers downlink data to be sent to the user equipment;

a triggering unit, configured to: when the first determining unitdetermines that the first indication information is set, trigger theserver that buffers the downlink data to send the downlink data to theuser equipment; and

a retaining unit, configured to: when the first determining unitdetermines that the first indication information is set, retain asignaling connection to the user equipment, so as to wait to send thedownlink data to the user equipment.

With reference to the fourth aspect, in a first possible implementationmanner of the fourth aspect, the triggering unit is configured to:

send a downlink data delivery request message to the server that buffersthe downlink data, so as to trigger the server that buffers the downlinkdata to send the downlink data to the user equipment; or

the triggering unit is configured to:

send a first user equipment reachability notification message to a homesubscriber server or home location register to which the user equipmentbelongs, so that the home subscriber server or the home locationregister sends a second user equipment reachability notification messageto the server that buffers the downlink data, so as to trigger theserver that buffers the downlink data to send the downlink data to theuser equipment.

With reference to the fourth aspect or the first possible implementationmanner of the fourth aspect, in a second possible implementation mannerof the fourth aspect, the retaining unit is configured to:

send a second message including second indication information to theuser equipment, where the second indication information indicates thatthere is data to be sent to the user equipment, so as to retain thesignaling connection to the user equipment.

With reference to the second possible implementation manner of thefourth aspect, in a third possible implementation manner of the fourthaspect, the retaining unit is configured to:

when duration, preset for the user equipment, in which a signalingconnection can be retained is less than a predetermined threshold, sendthe second message to the user equipment.

With reference to the first possible implementation manner of the fourthaspect, the second possible implementation manner of the fourth aspect,or the third possible implementation manner of the fourth aspect, in afourth possible implementation manner of the fourth aspect, the corenetwork control entity further includes:

a first sending unit, configured to: when it is determined that thefirst indication information is not set, send a third message includingthird indication information to the user equipment, where the thirdindication information indicates that there is no downlink data to besent to the user equipment, so that the user equipment disables areceiver or enters a power saving mode or shuts down according to thethird indication information.

With reference to the second possible implementation manner of thefourth aspect or the third possible implementation manner of the fourthaspect, in a fifth possible implementation manner of the fourth aspect,the second indication information further includes address informationof the server.

With reference to the first possible implementation manner of the fourthaspect, the second possible implementation manner of the fourth aspect,the third possible implementation manner of the fourth aspect, thefourth possible implementation manner of the fourth aspect, or the fifthpossible implementation manner of the fourth aspect, in a sixth possibleimplementation manner of the fourth aspect, the core network controlentity further includes:

a second determining unit, configured to: when the user equipment is atime-controlled user equipment, determine whether the current time iswithin a range of allowed communication time, where

the first determining unit is configured to:

when the second determining unit determines that the current time iswithin the range of allowed communication time of the user equipment,determine whether the first indication information is set.

With reference to the first possible implementation manner of the fourthaspect, the second possible implementation manner of the fourth aspect,the third possible implementation manner of the fourth aspect, thefourth possible implementation manner of the fourth aspect, the fifthpossible implementation manner of the fourth aspect, or the sixthpossible implementation manner of the fourth aspect, in a seventhpossible implementation manner of the fourth aspect, the core networkcontrol entity further includes:

a first receiving unit, configured to receive a second user equipmentreachability notification request message that is sent by the homesubscriber server or home location register to which the user equipmentbelongs after the home subscriber server or home location registerreceives a first user equipment reachability notification requestmessage, and a first setting unit, configured to set the firstindication information according to the second user equipmentreachability notification request message received by the firstreceiving unit; or includes:

a second receiving unit, configured to receive data buffering indicationinformation sent by the server that buffers the downlink data, where thedata buffering indication information indicates that the server buffersthe downlink data to be sent to the user equipment, and a second settingunit, configured to set the first indication information according tothe data buffering indication information.

With reference to the first possible implementation manner of the fourthaspect, the second possible implementation manner of the fourth aspect,the third possible implementation manner of the fourth aspect, thefourth possible implementation manner of the fourth aspect, the fifthpossible implementation manner of the fourth aspect, or the sixthpossible implementation manner of the fourth aspect, in an eighthpossible implementation manner of the fourth aspect, the core networkcontrol entity further includes:

a third receiving unit, configured to receive a context response messagesent by a source core network control entity serving the user equipment;and

a third setting unit, configured to: when the context response messagereceived by the third receiving unit includes the first indicationinformation, set the first indication information.

With reference to the first possible implementation manner of the fourthaspect, the second possible implementation manner of the fourth aspect,the third possible implementation manner of the fourth aspect, thefourth possible implementation manner of the fourth aspect, the fifthpossible implementation manner of the fourth aspect, the sixth possibleimplementation manner of the fourth aspect, the seventh possibleimplementation manner of the fourth aspect, or the eighth possibleimplementation manner of the fourth aspect, in a ninth possibleimplementation manner of the fourth aspect, the core network controlentity further includes:

a first deleting unit, configured to: when determining, according to thefirst indication information, that a validity period of the downlinkdata expires, delete the first indication information, where the firstindication information is further used to indicate the validity periodof the downlink data, and the validity period, indicated by the firstindication information, of the downlink data is set according to avalidity period, of the downlink data, carried in the data bufferingindication information sent by the server that buffers the downlinkdata; or includes:

a fourth receiving unit, configured to receive a fourth message that issent, after a validity period of the downlink data expires, by theserver that buffers the downlink data, where the fourth message is usedas an instruction to delete the first indication information, and asecond deleting unit, configured to delete the first indicationinformation according to the fourth message received by the fourthreceiving unit; or includes:

a fifth receiving unit, configured to receive a first user equipmentreachability notification cancellation message sent by the homesubscriber server or home location register to which the user equipmentbelongs, and a third deleting unit, configured to delete the firstindication information according to the first user equipmentreachability notification cancellation message received by the fifthreceiving unit.

With reference to the ninth possible implementation manner of the fourthaspect, in a tenth possible implementation manner of the fourth aspect,the fifth receiving unit is configured to:

receive the first user equipment reachability notification cancellationmessage that is sent by the home subscriber server or the home locationregister according to a second user equipment reachability notificationcancellation message sent by the server that buffers the downlink dataof the user equipment; or

receive the first user equipment reachability notification cancellationmessage that is sent by the home subscriber server or the home locationregister after the home subscriber server or the home location registerdetermines, according to the first user equipment reachabilitynotification request message, that the downlink data expires, where thefirst user equipment reachability notification request message carriesthe validity period of the downlink data.

With reference to the second possible implementation manner of thefourth aspect or the third possible implementation manner of the fourthaspect, in an eleventh possible implementation manner of the fourthaspect, the core network control entity further includes an establishingunit:

configured to: after a downlink data notification message or downlinkdata sent by the server that buffers the downlink data is received,establish an evolved universal terrestrial radio access network radioaccess bearer corresponding to a bearer for transmitting a correspondingdata packet or establish a radio access bearer corresponding to a PacketData Protocol context for transmitting a corresponding data packet; or

configured to establish a user plane bearer or a Packet Data Protocolcontext.

According to a fifth aspect, a user equipment is provided, including:

a sending unit, configured to send a first message to a core networkcontrol entity; and

a power saving unit, configured to: when receiving a third message thatincludes third indication information and is sent by the core networkcontrol entity according to the first message, disable a receiver orenable the user equipment to enter a power saving mode or shut down,where the third indication information indicates that a server has nodownlink data to be sent to the user equipment.

With reference to the fifth aspect, in a first possible implementationmanner of the fifth aspect, the user equipment further includes:

a retaining unit, configured to: when receiving a second message thatincludes second indication information and is sent by the core networkcontrol entity according to the first message, retain an establishedsignaling connection, so as to wait to receive downlink data, where thesecond indication information indicates that the server has downlinkdata to be sent to the user equipment.

With reference to the fifth aspect or the first possible implementationmanner of the fifth aspect, in a second possible implementation mannerof the fifth aspect, when the user equipment includes the retainingunit, the user equipment further includes:

a determining unit, configured to: when a current access network is ageneral packet radio service technology network, determine whether aPacket Data Protocol context is reserved; and

an initiating unit, configured to: when no Packet Data Protocol contextis reserved, initiate a Packet Data Protocol context process, so as toestablish a Packet Data Protocol context.

According to a sixth aspect, a server is provided, including a firstsending unit, a first receiving unit, and a second sending unit, where

the first sending unit is configured to send a first user equipmentreachability notification request message to a home subscriber server orhome location register to which a user equipment belongs, so that thehome subscriber server or the home location register sends a second userequipment reachability notification request message to a core networkcontrol entity to which the user equipment belongs, and therefore thecore network control entity sets first indication information accordingto the second user equipment reachability notification request message,where the first indication information indicates that the server buffersdownlink data to be sent to the user equipment; the first receiving unitis configured to receive a second user equipment reachabilitynotification message that is sent by the home subscriber server or thehome location register after the home subscriber server or the homelocation register receives a first user equipment reachabilitynotification message that is sent by the core network control entityaccording to the first indication information; and the second sendingunit is configured to send the downlink data to the user equipment; or

the first sending unit is configured to send data buffering indicationinformation to a core network control entity to which a user equipmentbelongs, so that the core network control entity sets first indicationinformation according to the data buffering indication information,where the data buffering indication information indicates that theserver buffers downlink data to be sent to the user equipment and thefirst indication information indicates that the server buffers thedownlink data to be sent to the user equipment; the first receiving unitis configured to receive a downlink data delivery request message thatis sent by the core network control entity according to the firstindication information; and the second sending unit is configured tosend the downlink data to the user equipment.

With reference to the sixth aspect, in a first possible implementationmanner of the sixth aspect, the server further includes: a third sendingunit, configured to: when determining that the downlink data expires,send a second user equipment reachability notification cancellationmessage to the home subscriber server or the home location register, sothat the home subscriber server or the home location register sends afirst user equipment reachability notification cancellation message tothe core network control entity, and therefore the core network controlentity deletes the first indication information according to the firstuser equipment reachability notification cancellation message; or

the first user equipment reachability notification request messagefurther includes a validity period of the downlink data, so that thehome subscriber server sends a first user equipment reachabilitynotification cancellation message to the core network control entitywhen determining, according to the first user equipment reachabilitynotification request message, that the validity period of the downlinkdata expires, and therefore the core network control entity deletes thefirst indication information according to the first user equipmentreachability notification cancellation message.

With reference to the sixth aspect, in a second possible implementationmanner of the sixth aspect, the server further includes a fourth sendingunit, configured to: when determining that a validity period of thedownlink data expires, send a fourth message to the core network controlentity, where the fourth message is used to instruct the core networkcontrol entity to delete the first indication information; or

the data buffering indication information further includes a validityperiod of the downlink data, so that the core network control entitysets the first indication information that is further used to indicatethe validity period of the downlink data, and deletes the firstindication information when the validity period of the downlink dataexpires.

Therefore, in the embodiments of the present invention, after the firstmessage sent by the user equipment is received, it is determined whetherthe first indication information is set, where the first indicationinformation indicates that the server buffers the downlink data to besent to the user equipment, and the signaling connection to the userequipment is retained only when it is determined that the firstindication information is set, which can reduce signaling consumption ina process of sending downlink data, and avoid a process of disconnectingand reestablishing a signaling connection between a user equipment and anetwork entity, thereby avoiding frequent status changes of the userequipment and the network entity, and saving power of the userequipment.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments of the presentinvention more clearly, the following briefly introduces theaccompanying drawings required for describing the embodiments of thepresent invention. Apparently, the accompanying drawings in thefollowing description show merely some embodiments of the presentinvention, and a person of ordinary skill in the art may still deriveother drawings from these accompanying drawings without creativeefforts.

FIG. 1 is a schematic flowchart of a method for transmitting dataaccording to an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a method for transmitting dataaccording to another embodiment of the present invention;

FIG. 3 is a schematic flowchart of a method for transmitting dataaccording to another embodiment of the present invention;

FIG. 4 is a schematic flowchart of a method for transmitting dataaccording to another embodiment of the present invention;

FIG. 5 is a schematic flowchart of a method for transmitting dataaccording to another embodiment of the present invention;

FIGS. 6A and 6B are a schematic flowchart of a method for transmittingdata according to another embodiment of the present invention;

FIG. 7 is a schematic flowchart of a method for transmitting dataaccording to another embodiment of the present invention;

FIG. 8 is a schematic flowchart of a method for transmitting dataaccording to another embodiment of the present invention;

FIG. 9A and FIG. 9B are a schematic flowchart of a method fortransmitting data according to another embodiment of the presentinvention;

FIG. 10 is a schematic block diagram of a core network control entityaccording to an embodiment of the present invention;

FIG. 11 is a schematic block diagram of a core network control entityaccording to another embodiment of the present invention;

FIG. 12 is a schematic block diagram of a core network control entityaccording to another embodiment of the present invention;

FIG. 13 is a schematic block diagram of a core network control entityaccording to another embodiment of the present invention;

FIG. 14 is a schematic block diagram of a user equipment according to anembodiment of the present invention;

FIG. 15 is a schematic block diagram of a user equipment according toanother embodiment of the present invention;

FIG. 16 is a schematic block diagram of a user equipment according toanother embodiment of the present invention;

FIG. 17 is a schematic block diagram of a server according to anembodiment of the present invention;

FIG. 18 is a schematic block diagram of a server according to anotherembodiment of the present invention; and

FIG. 19 is a schematic block diagram of a server according to anotherembodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The following clearly describes the technical solutions in theembodiments of the present invention with reference to the accompanyingdrawings in the embodiments of the present invention. Apparently, thedescribed embodiments are a part rather than all of the embodiments ofthe present invention. All other embodiments obtained by a person ofordinary skill in the art based on the embodiments of the presentinvention without creative efforts shall fall within the protectionscope of the present invention.

It should be understood that, the technical solutions of the embodimentsof the present invention can be applied to various communicationssystems, such as: a Global System for Mobile Communications (GSM)system, a Code Division Multiple Access (CDMA) system, a Wideband CodeDivision Multiple Access (WCDMA) system, a general packet radio service(GPRS) system, a Long Term Evolution (LTE) system, an LTE frequencydivision duplex (FDD) system, an LTE time division duplex (TDD), and aUniversal Mobile Telecommunications System (UMTS).

A user equipment (UE) may also be referred to as a terminal and maycommunicate with one or more core networks by using a radio accessnetwork (RAN).

When ordinal numbers, such as “first”, “second”, “third”, “fourth”, and“fifth”, are mentioned in the present invention, it should be understoodthat they are merely used for distinguishing unless they actuallyexpress a sequence according to a context.

FIG. 1 is a schematic flowchart of a method 100 for transmitting dataaccording to an embodiment of the present invention. The method 100 maybe executed by a core network control entity, for example, an SGSN or anMME. As shown in FIG. 1, the method 100 includes:

S110: After receiving a first message sent by a user equipment,determine whether first indication information is set, where the firstindication information indicates that a server buffers downlink data tobe sent to the user equipment.

S120: When determining that the first indication information is set,retain a signaling connection to the user equipment, and trigger theserver that buffers the downlink data to send the downlink data to theuser equipment.

Specifically, after receiving the first message, for example, a TAU/RAUrequest message, an attach request message, or a service requestmessage, sent by the user equipment, the core network control entity,for example, an SGSN or an MME, may check whether the first indicationinformation indicating that the server buffers the downlink data to besent to the user equipment is set in the core network control entity;after determining that the first indication information is set, the corenetwork control entity may retain the signaling connection to the userequipment and trigger the server that buffers the downlink data to sendthe downlink data to the user equipment, so that the core networkcontrol entity sends the downlink data to the user equipment by usingthe retained signaling connection to the user equipment after receivingdownlink data or a downlink data notification that is to be sent by theserver to the user equipment.

In the embodiment of the present invention, the triggering the serverthat buffers the downlink data to send the downlink data to the userequipment can be implemented in the following two manners.

Manner 1: Directly send a downlink data delivery request to the serverthat buffers the downlink data, so as to request the server that buffersthe downlink data to send the downlink data to the user equipment.

Manner 2: Send a first user equipment reachability notification messageto a home subscriber server or home location register to which the userequipment belongs, so that the home subscriber server or the homelocation register sends a second user equipment reachabilitynotification message to the server according to the first user equipmentreachability notification message sent by the core network controlentity, the server may determine, by using the second user equipmentreachability notification message, that the user equipment is reachable,and therefore the server may send the buffered downlink data to the userequipment.

In the embodiment of the present invention, that a user equipment isreachable means that the user equipment can respond to a paging messageor retain a signaling connection to a core network control entity, forexample, a user equipment is reachable in a period of time after theuser equipment sends a TAU/RAU request message and sends an uplink datarequest. In the embodiment of the present invention, that a server sendsa user equipment reachability notification request message to a homesubscriber server or home location register to which the user equipmentbelongs means that the server sends the user equipment reachabilitynotification request message to the home subscriber server or the homelocation register, so as to request receiving of a notification when theuser equipment is reachable. After receiving a second user equipmentreachability notification that the home subscriber server or the homelocation register sends after receiving a first user equipmentreachability notification sent by the core network control entity, theserver may determine that the user equipment is reachable, and thereforethe server may send downlink data to the user equipment.

After retaining the signaling connection for a certain period of time,the user equipment may enter an idle mode or a power saving state, orshut down, so as to save power.

Therefore, according to the method for transmitting data in theembodiment of the present invention, after the first message sent by theuser equipment is received, it is determined whether the firstindication information is set, where the first indication informationindicates that the server buffers the downlink data to be sent to theuser equipment, and the signaling connection to the user equipment isretained only when it is determined that the first indicationinformation is set, which can reduce signaling consumption in a processof sending downlink data, and avoid a process of disconnecting andreestablishing a signaling connection between a user equipment and anetwork entity, thereby avoiding frequent status changes of the userequipment and the network entity, and saving power of the userequipment.

In the embodiment of the present invention, the retaining a signalingconnection to the user equipment in S120 includes:

sending a second message including second indication information to theuser equipment, where the second indication information indicates thatthere is data to be sent to the user equipment, so as to retain thesignaling connection to the user equipment.

Specifically, the core network control entity may send, to the userequipment by using the second message, for example, a TAU/RAU acceptmessage, an attach accept message, a direct transfer message, a serviceaccept message, or another NAS message such as a downlink NAS transportmessage, the second indication information used to indicate that thereis data to be sent to the user equipment, so that, after receiving thesecond message that includes the second indication information and issent by the core network control entity, the user equipment remains in acommunication-capable state, that is, retains the signaling connectionto the core network control entity, so as to wait to receive thedownlink data sent by the server.

In the embodiment of the present invention, the retaining a signalingconnection to the user equipment means that the core network controlentity does not initiate a signaling connection release process, and forthe user equipment, an established RRC connection is retained and notreleased, that is, a timer T3440 or T3340 specified in an existingstandard is not started; and if the user equipment retains the signalingconnection for a predetermined period of time, and receives the secondmessage sent by the core network control entity after the timer T3440 orT3340 is started, the timer T3440 or T3340 may be deleted.

In the embodiment of the present invention, the sending the secondmessage including the second indication information to the userequipment may include:

when duration, preset for the user equipment, in which a signalingconnection can be retained is less than a predetermined threshold,sending the second message to the user equipment.

Specifically, when determining that the first indication information isset in the core network control entity, the core network control entitymay determine whether the duration, preset for the user equipment, inwhich a signaling connection can be retained is less than thepredetermined threshold, and sends the second message including thesecond indication information to the user equipment only when theduration is less than the predetermined threshold.

In the embodiment of the present invention, the method 100 may furtherinclude:

when determining that the first indication information is not set,sending a third message including third indication information to theuser equipment, where the third indication information indicates thatthere is no downlink data to be sent to the user equipment, so that theuser equipment disables a receiver or enters a power saving mode orshuts down according to the third indication information.

Specifically, the core network control entity may generate the thirdindication information after receiving the first message sent by theuser equipment and when determining that the first indicationinformation is not set in the core network control entity, where thethird indication information indicates that there is no downlink data tobe sent to the user equipment; and then, may send the third indicationinformation to the user equipment by using the third message, forexample, a TAU/RAU accept message, an attach accept message, a directtransfer message, a service accept message, or another NAS message, sothat the user equipment may disable the receiver, may enter the powersaving mode, or may shut down after receiving the third message thatincludes the third indication information and is sent by the corenetwork control entity.

Therefore, in the embodiment of the present invention, after it isdetermined that the first indication information indicating that theserver buffers the downlink data to be sent to the user equipment is notset, the third message that includes the third indication informationindicating that the server has no downlink data to be sent to the userequipment is sent to the user equipment, so that the user equipmentdisables the receiver or enters the power saving mode or shuts downafter receiving the third message that includes the third indicationinformation and is sent by the server, and therefore power can be saved.

In the embodiment of the present invention, the second indicationinformation may further include address information of a server, so thatthe user equipment may disable the receiver, enter the power savingmode, or shut down after receiving data sent by a server correspondingto the server address information included in the second indicationinformation, which can further save power.

When multiple servers are to send data to the user equipment, the secondindication information may include address information of the multipleservers, so that the user equipment disables the receiver, enters thepower saving mode, or shuts down after receiving the data from themultiple servers.

For a time-controlled user equipment, triggering, according to a firstmessage, an SCS (or MTC SERVER) to send downlink data may occur beyond arange of allowed communication time for the time-controlled userequipment, and an evolved packet system (EPS) network needs to reject ordiscard data to be sent. In this case, extra load is caused to thenetwork.

Therefore, in the embodiment of the present invention, before thedetermining, after receiving a first message sent by a user equipment,whether first indication information is stored, the method 100 mayfurther include:

when the user equipment is a time-controlled user equipment, determiningwhether the current time is within a range of allowed communicationtime; where

the determining whether first indication information is stored includes:

when determining that the current time is within the range of allowedcommunication time of the user equipment, determining whether the firstindication information is set.

Specifically, after receiving the first message sent by the userequipment, the core network control entity may determine whether theuser equipment is a time-controlled user equipment according tosubscription data of the user equipment. If determining that the userequipment is a time-controlled user equipment, the core network controlentity may further determine whether the current time is within therange of allowed communication time of the user equipment according tothe subscription data of the user equipment, and determines whether thefirst indication information is set only when determining that thecurrent time is within the range of allowed communication time of theuser equipment.

In the embodiment of the present invention, when the user equipment isnot within the range of allowed communication time, the subsequentprocess of the embodiment of the present invention is not executed. Fora subsequent implementation manner, reference may be made to theconventional art. For brevity, details are not repeatedly describedherein.

Therefore, according to the method for transmitting data in theembodiment of the present invention, only after it is determined thatthe current time is within the range of allowed communication time ofthe user equipment, it is determined whether the first indicationinformation is set, which reduces network load.

In the embodiment of the present invention, before the determiningwhether first indication information is set in S110, the method 100 mayfurther include:

receiving data buffering indication information sent by the server thatbuffers the downlink data, where the data buffering indicationinformation indicates that the server buffers the downlink data to besent to the user equipment, and setting the first indication informationaccording to the data buffering indication information.

Specifically, in the embodiment of the present invention, when theserver needs to send the downlink data to the user equipment, andcurrent time is beyond a time range for sending downlink data to theuser equipment, the server may buffer the downlink data and send, to thecore network control entity, the data buffering indication informationindicating that the server buffers the downlink data to be sent to theuser equipment. After receiving the data buffering indicationinformation sent by the server, the core network control entity may setthe first indication information.

Alternatively, in the embodiment of the present invention, before thedetermining whether first indication information is set in S110, themethod 100 may further include: receiving a second user equipmentreachability notification request message that is sent by the homesubscriber server or home location register to which the user equipmentbelongs after the home subscriber server or home location registerreceives a first user equipment reachability notification requestmessage, and setting the first indication information according to thesecond user equipment reachability notification request message.

Specifically, when the server needs to send the downlink data to theuser equipment, and current time is beyond a time range for sendingdownlink data to the user equipment, the server may buffer the downlinkdata and send the first user equipment reachability notification requestmessage to the home subscriber server or home location register to whichthe user equipment belongs, where the first user equipment reachabilitynotification request message may carry address information of the serverand identity information of the user equipment. Then, the homesubscriber server or the home location register may send, according tothe first user equipment reachability notification request message, thesecond user equipment reachability notification request message to thecore network control entity to which the user equipment belongs, wherethe second user equipment reachability notification request message maycarry the identity information of the user equipment. After receivingthe second user equipment reachability notification request message sentby the home subscriber server or the home location register, the corenetwork control entity may set the first indication information.

Alternatively, in the embodiment of the present invention, before thedetermining whether the first indication information is stored in S110,the method 100 may further include:

receiving a context response message sent by a source core networkcontrol entity serving the user equipment; and

when the context response message includes the first indicationinformation, setting the first indication information.

Specifically, in a TAU/RAU process of the user equipment, if a corenetwork control entity to which the user equipment is attached changes,the core network control entity may send a context request message tothe source core network control entity serving the user equipment toacquire user information, receive the context response message sent bythe source core network control entity serving the user equipment, andset the first indication information when determining that the contextresponse message includes the first indication information.

Before the determining, after receiving a first message sent by a userequipment, whether first indication information is set, the method 100may further include:

when determining, according to the first indication information, that avalidity period of the downlink data expires, deleting the firstindication information, where the first indication information isfurther used to indicate the validity period of the downlink data, andthe validity period, indicated by the first indication information, ofthe downlink data is set according to a validity period, of the downlinkdata, carried in the data buffering indication information sent by theserver that buffers the downlink data.

Specifically, if the downlink data that is buffered in the server and isto be sent to the user equipment has a validity period, the databuffering indication information sent by the server to the userequipment further indicates the validity period of the downlink datathat is buffered in the server and is to be sent to the user equipment.After receiving the data buffering indication information sent by theserver, the core network control entity may set the first indicationinformation that is further used to indicate the validity period of thedownlink data. If the validity period expires but corresponding data isnot sent yet, the core network control entity may delete the firstindication information.

Alternatively, in the embodiment of the present invention, before thedetermining, after receiving a first message sent by a user equipment,whether first indication information is set, the method 100 may furtherinclude:

receiving a fourth message that is sent, after a validity period of thedownlink data expires, by the server that buffers the downlink data,where the fourth message is used as an instruction to delete the firstindication information, and deleting the first indication informationaccording to the fourth message.

Specifically, if the downlink data that is buffered in the server and isto be sent to the user equipment has a validity period, and if thevalidity period expires but corresponding data is not sent yet, theserver may instruct the core network control entity to delete the firstindication information that is stored, so that the core network controlentity may delete the first indication information according to theinstruction of the server.

Alternatively, in the embodiment of the present invention, before thedetermining, after receiving a first message sent by a user equipment,whether first indication information is set, the method 100 may furtherinclude:

receiving a first user equipment reachability notification cancellationmessage sent by the home subscriber server or home location register towhich the user equipment belongs, and deleting the first indicationinformation according to the first user equipment reachabilitynotification cancellation message.

In the embodiment of the present invention, the receiving a first userequipment reachability notification cancellation message sent by thehome subscriber server or the home location register may include:

receiving the first user equipment reachability notificationcancellation message that is sent by the home subscriber server or thehome location register according to a second user equipment reachabilitynotification cancellation message sent by the server that buffers thedownlink data of the user equipment; or includes:

receiving the first user equipment reachability notificationcancellation message that is sent by the home subscriber server or thehome location register after the home subscriber server or the homelocation register determines, according to the first user equipmentreachability notification request message, that the downlink dataexpires, where the first user equipment reachability notificationrequest message carries the validity period of the downlink data.

It should be understood that, in the embodiment of the presentinvention, the first indication information may be used to indicate thatmultiple servers have downlink data to be sent to the user equipment.After receiving a user equipment reachability notification cancellationmessage sent by any server or determining that data to be sent by anyserver to the user equipment expires, the home subscriber server or thehome location register may delete user equipment reachability-relatedinformation of the any server. After deleting all user equipmentreachability-related information of the multiple servers, that is, thereis no notification request for user equipment reachability, the homesubscriber server or the home location register instructs the corenetwork control entity to delete the first indication information.

In the conventional art, only by using a TAU/RAU request message, aserver can be triggered to send buffered downlink data to a userequipment. For a low-mobility device, few or even no TAU/RAU process isperformed. In this case, sending data by the server to the userequipment is possibly affected because to-be-sent data buffered in theserver may become invalid or be deleted after a certain period of time.However, in the embodiment of the present invention, the first messagemay be a TAU/RAU request message, may be an attach request message, ormay be a service request message. Therefore, chances for the server tosend buffered downlink data to the user equipment can be increased,which prevents data from becoming invalid or being deleted.

In the embodiment of the present invention, the method 100 may furtherinclude:

after receiving a downlink data notification message or downlink datasent by the server that buffers the downlink data, establishing anevolved universal terrestrial radio access network radio access bearer(E-RAB) corresponding to a bearer for transmitting a corresponding datapacket or establishing a radio access bearer (RAB) corresponding to aPacket Data Protocol (PDP) context for transmitting a corresponding datapacket.

Specifically, when determining that the first indication information isset, the core network control entity retains the signaling connection tothe user equipment, where the signaling connection to the user equipmentmay be retained by sending the second message including the secondindication information to the user equipment; and the retaining thesignaling connection to the user equipment means that the core networkcontrol entity does not initiate a signaling connection release process,and for the user equipment, an established RRC connection is retainedand not released, that is, a timer T3440 or T3340 specified in anexisting standard is not started; and if the user equipment retains thesignaling connection for a predetermined period of time, and receivesthe second message sent by the core network control entity after thetimer T3440 or T3340 is started, the timer T3440 or T3340 may bedeleted. After receiving a request that is sent by the core networkcontrol entity and is used to instruct the server to send the downlinkdata to the user equipment, or the second user equipment reachabilitynotification message that is sent by the home subscriber server or thehome location register after the home subscriber server or the homelocation register receives the first user equipment reachabilitynotification message sent by the core network control entity, the serverstarts to send the downlink data. For a System Architecture Evolution(SAE) network, after a core network control entity receives a downlinkdata notification message, or for a general packet radio service (GPRS)network, after an SGSN receives downlink data, the core network controlentity may directly require a radio access network (RAN) side (forexample, an eNodeB or a radio network controller (RNC)) to establish anevolved universal terrestrial radio access network radio access bearer(E-RAB) corresponding to a bearer for transmitting a corresponding datapacket or establish a radio access bearer (RAB) corresponding to aPacket Data Protocol PDP context for transmitting a corresponding datapacket. For example, for the SAE network, an MME sends an initialcontext setup message to an eNodeB according to an EPS bearer identifier(ID) in a received downlink data notification, so as to establish acorresponding E-RAB (radio bearer and S1 bearer); for the GPRS network,an SGSN sends a radio access bearer assignment message to an RNC, so asto establish a corresponding RAB (a user plane between the userequipment, the RNC, and the SGSN).

Alternatively, in the embodiment of the present invention, the method100 may further include:

establishing a user plane or a PDP context.

Specifically, when determining that the first indication information isset, the core network control entity may retain the signaling connectionto the user equipment, where the signaling connection to the userequipment may be retained by sending the second message including thesecond indication information to the user equipment, and the retainingthe signaling connection to the user equipment means that the corenetwork control entity does not initiate a signaling connection releaseprocess, and for the user equipment, an established RRC connection isretained and not released, that is, a timer T3440 or T3340 specified inan existing standard is not started; and if the user equipment retainsthe signaling connection for a predetermined period of time, andreceives the second message sent by the core network control entityafter the timer T3440 or T3340 is started, the timer T3440 or T3340 maybe deleted. The core network control entity may execute a process ofestablishing E-RABs of all bearers or RABs of all PDP contexts at thesame time when sending the second message including the secondindication information to the user equipment, or may execute a processof establishing E-RABs of all bearers or RABs of all PDP contexts whendetermining that the first indication information is set. For an SAEnetwork, it refers to establishing of radio bearers that are between theuser equipment and an eNodeB and are corresponding to all activatedbearers of the user equipment, and establishing of an S1 user planeconnection between the eNodeB and a serving gateway (SGW); and for aUMTS network, it refers to establishing of radio bearers that arebetween the user equipment and an RNC and are corresponding to allactivated PDP contexts of the user, and establishing of an Iu user planeconnection between the RNC and an SGSN. For a bearer for which noE-RAB/RAB is successfully established, the user equipment and thenetwork release the bearer or the PDP context.

Alternatively, in the embodiment of the present invention, thetriggering the server that buffers the downlink data to send thedownlink data to the user equipment may include:

when a network that the user equipment currently accesses is a GPRSnetwork and it is determined that a PDP context has been established forthe user equipment, triggering the server to send the buffered downlinkdata to be sent to the user equipment.

Specifically, for a GPRS network, if no PDP context is reserved, afterreceiving the second message (a TAU/RAU response message or an attachaccept message) that includes the second indication information and issent by the core network control entity, the user equipment initiates aprocess of activating a PDP context, so as to establish a PDP context.After it is determined that the PDP context has been established for theuser equipment, that is, after an SGSN receives an active PDP contextaccept message sent by the user equipment, the core network controlentity triggers the server to send the downlink data, where a parameterused by the user equipment to initiate the process of activating the PDPcontext may be preconfigured on the user equipment.

Therefore, according to the method for transmitting data in theembodiment of the present invention, after the first message sent by theuser equipment is received, it is determined whether first indicationinformation is set, where the first indication information indicatesthat the server buffers the downlink data to be sent to the userequipment. When it is determined that the first indication informationis set, the signaling connection to the user equipment is retained.After it is determined that the first indication information indicatingthat the server buffers the downlink data to be sent to the userequipment is not stored, the third message that includes the thirdindication information indicating that the server has no downlink datato be sent to the user equipment is sent to the user equipment, so thatthe user equipment disables the receiver or enters the power saving modeor shuts down after receiving the third message that includes the thirdindication information and is sent by the server, and therefore powercan be saved, and power of the user equipment can be saved. Further,when determining that the server has the downlink data to be sent to theuser equipment, the core network control entity establishes a bearerrequired for sending the downlink data, thereby saving time required fortransmitting the downlink data. Further, in the embodiment of thepresent invention, only after it is determined that the current time iswithin the range of allowed communication time of the user equipment, itis determined whether the first indication information is set, whichreduces network load. Further, in the embodiment of the presentinvention, the first message may be a TAU/RAU request message, an attachrequest message, or a service request message, so that chances for theserver to send buffered downlink data to the user equipment can beincreased, which prevents data from becoming invalid or being deleted.

The foregoing already describes the method 100 for transmitting data ofthe embodiments of the present invention from a core network controlentity side with reference to FIG. 1. The following describes a methodfor transmitting data of the embodiments of the present invention from auser equipment side with reference to FIG. 2.

FIG. 2 is a schematic flowchart of a method 200 for transmitting dataaccording to an embodiment of the present invention. The method may beexecuted by a user equipment. As shown in FIG. 2, the method 200includes:

S210: Send a first message to a core network control entity.

S220: When receiving a third message that includes third indicationinformation and is sent by the core network control entity according tothe first message, disable a receiver or enable the user equipment toenter a power saving mode or shut down, where the third indicationinformation indicates that a server has no downlink data to be sent tothe user equipment.

Therefore, in the embodiment of the present invention, the userequipment sends the first message to the core network control entity,and after receiving the third message that includes the third indicationinformation and is sent by the core network control entity according tothe first message, disables the receiver or enters the power saving modeor shuts down, where the third indication information indicates thatthere is no downlink data to be sent to the user equipment, so thatpower of the user equipment can be saved.

In the embodiment of the present invention, the method 200 may furtherinclude:

when receiving a second message that includes second indicationinformation and is sent by the core network control entity according tothe first message, retaining an established signaling connection, so asto wait to receive downlink data, where the second indicationinformation indicates that there is downlink data to be sent to the userequipment.

Specifically, after receiving the second message that includes thesecond indication information and is sent by the core network controlentity (for example, an MME or an SGSN), the user equipment does notstart a timer T3440 or T3340 specified in a standard, keeps an RRCconnection unreleased, and waits for the downlink data sent by theserver.

Therefore, in the embodiment of the present invention, the userequipment keeps the RRC connection unreleased. This saves a pagingprocess and a process of reestablishing an RRC connection by the userequipment, and can further save power.

In the embodiment of the present invention, when the second message thatincludes the second indication information and is sent by the corenetwork control entity according to the first message is received, themethod 200 may further include:

when a current access network is a general packet radio servicetechnology network, determining whether a Packet Data Protocol contextis reserved; and

when no Packet Data Protocol context is reserved, initiating a PacketData Protocol context process, so as to establish a Packet Data Protocolcontext.

In the embodiment of the present invention, the first message may be atracking area update/routing area update (TAU/RAU) request message, andthe second message may be a TAU/RAU accept message; or the first messagemay be an attach request message, and the second message may be anattach response message; or the first message may be a service requestmessage, and the second message may be a direct transfer message or aservice accept message.

Therefore, in the embodiment of the present invention, the userequipment sends the first message to the core network control entity;after receiving the third message that includes the third indicationinformation and is sent by the core network control entity according tothe first message, disables the receiver or enters the power saving modeor shuts down, where the third indication information indicates thatthere is no downlink data to be sent to the user equipment; and afterreceiving the second message that includes the second indicationinformation and is sent by the core network control entity according tothe first message, retains the established signaling connection, so asto wait to receive the downlink data, where the second indicationinformation indicates that there is downlink data to be sent to the userequipment, so that power of the user equipment can be saved.

FIG. 3 is a schematic flowchart of a method 300 for transmitting dataaccording to an embodiment of the present invention. The method 300 isexecuted by a server, for example, an SCS or an MTC SERVER. As shown inFIG. 3, the method 300 may include:

S310: Send a first user equipment reachability notification requestmessage to a home subscriber server or home location register to which auser equipment belongs, so that the home subscriber server or the homelocation register sends a second user equipment reachabilitynotification request message to a core network control entity to whichthe user equipment belongs, and therefore the core network controlentity sets first indication information according to the second userequipment reachability notification request message, where the firstindication information indicates that the server buffers downlink datato be sent to the user equipment, and the server sends the downlink datato the user equipment when receiving a second user equipmentreachability notification message that is sent by the home subscriberserver or the home location register after the home subscriber server orthe home location register receives a first user equipment reachabilitynotification message that is sent by the core network control entityaccording to the first indication information; or

send data buffering indication information to a core network controlentity to which a user equipment belongs, so that the core networkcontrol entity sets first indication information according to the databuffering indication information, where the data buffering indicationinformation indicates that the server buffers downlink data to be sentto the user equipment and the first indication information indicatesthat the server buffers the downlink data to be sent to the userequipment, and the server sends the downlink data to the user equipmentwhen receiving a downlink data delivery request message that is sent bythe core network control entity according to the first indicationinformation.

Specifically, in the embodiment of the present invention, whendetermining that there is downlink data to be sent to the userequipment, if current time is beyond a time range for sending downlinkdata to the user equipment, the server may buffer corresponding downlinkdata. Then, the server may send the data buffering indicationinformation to the core network control entity, so that the core networkcontrol entity may set the first indication information according to thedata buffering indication information, and after receiving the firstmessage sent by the user equipment, may retain, according to the firstindication information, a signaling connection to the user equipment andrequest the server to send the downlink data to the user equipment.Therefore, the core network control entity may use the retainedsignaling connection to send, to the user equipment, the downlink datathat is to be sent to the user equipment and is sent by the server.

Alternatively, in the embodiment of the present invention, whendetermining that there is downlink data to be sent to the userequipment, if current time is beyond a time range for sending downlinkdata to the user equipment, the server may buffer corresponding downlinkdata. Then, the server may send the first user equipment reachabilitynotification request message to the home subscriber server or homelocation register to which the user equipment belongs, where the firstuser equipment reachability notification request message may carryidentity information of the user equipment or address information of theserver. The home subscriber server or home location register to whichthe user equipment belongs sends the second user equipment reachabilitynotification request message to the core network control entity, wherethe second user equipment reachability notification request message maycarry the identity information of the user equipment. After receivingthe second user equipment reachability notification request message sentby the home subscriber server or home location register to which theuser equipment belongs, the core network control entity may set thefirst indication information indicating that the server buffers thedownlink data to be sent to the user equipment, and after receiving thefirst message sent by the user equipment, may retain, according to thefirst indication information, a signaling connection to the userequipment and request the server to send the downlink data to the userequipment. Therefore, the core network control entity may use theretained signaling connection to send, to the user equipment, thedownlink data that is to be sent to the user equipment and is sent bythe server.

Therefore, in the embodiment of the present invention, the server sendsthe first user equipment reachability notification request message tothe home subscriber server or the home location register, so that thehome subscriber server or the home location register sends the seconduser equipment reachability notification request message to the corenetwork control entity, and therefore the core network control entitysets the first indication information according to the second userequipment reachability notification request message, where the firstindication information indicates that the server buffers the downlinkdata to be sent to the user equipment, and the server sends the downlinkdata to the user equipment when receiving a second user equipmentreachability notification response message that is sent by the homesubscriber server or the home location register after the homesubscriber server or the home location register receives a first userequipment reachability notification response message that is sent by thecore network control entity according to the first indicationinformation; or sends the data buffering indication information to thecore network control entity, so that the core network control entitysets the first indication information according to the data bufferingindication information, where the data buffering indication informationindicates that the server buffers the downlink data to be sent to theuser equipment and the first indication information indicates that theserver buffers the downlink data to be sent to the user equipment, andthe server sends the downlink data to the user equipment when receivinga request message that is sent by the core network control entityaccording to the first indication information and triggers the downlinkdata, which can save power of the user equipment.

In the embodiment of the present invention, when the method 300 includesthe sending a first user equipment reachability notification requestmessage to a home subscriber server or home location register, themethod 300 may further include:

when determining that the downlink data expires, sending a second userequipment reachability notification cancellation message to the homesubscriber server or the home location register, so that the homesubscriber server or the home location register sends a first userequipment reachability notification cancellation message to the corenetwork control entity, and therefore the core network control entitydeletes the first indication information according to the first userequipment reachability notification cancellation message; or

the first user equipment reachability notification request message mayfurther include a validity period of the downlink data, so that the homesubscriber server or the home location register sends a first userequipment reachability notification cancellation message to the userequipment when determining, according to the first user equipmentreachability notification request message, that the validity period ofthe downlink data expires, and therefore the core network control entitydeletes the first indication information according to the first userequipment reachability notification cancellation message.

In the embodiment of the present invention, when the method 300 mayinclude the sending data buffering indication information to a corenetwork control entity, the method further includes: when determiningthat a validity period of the downlink data expires, sending a fourthmessage to the core network control entity, where the fourth message isused to instruct the core network control entity to delete the firstindication information; or the data buffering indication information mayfurther include a validity period of the downlink data, so that the corenetwork control entity sets the first indication information that isfurther used to indicate the validity period of the downlink data, anddeletes the first indication information when the validity period of thedownlink data expires.

Therefore, in the embodiment of the present invention, the server sendsthe first user equipment reachability notification request message tothe home subscriber server or the home location register, so that thehome subscriber server or the home location register sends the seconduser equipment reachability notification request message to the corenetwork control entity, and therefore the core network control entitysets the first indication information according to the second userequipment reachability notification request message, where the firstindication information indicates that the server buffers the downlinkdata to be sent to the user equipment, and the server sends the downlinkdata to the user equipment when receiving a second user equipmentreachability notification response message that is sent by the homesubscriber server or the home location register after the homesubscriber server or the home location register receives a first userequipment reachability notification response message that is sent by thecore network control entity according to the first indicationinformation; or sends the data buffering indication information to thecore network control entity, so that the core network control entitysets the first indication information according to the data bufferingindication information, where the data buffering indication informationindicates that the downlink data to be sent to the user equipment isbuffered and the first indication information indicates that anotherentity has downlink data to be sent to the user equipment, and theanother entity sends the downlink data to the user equipment whenreceiving a request message that is sent by the core network controlentity according to the first indication information and triggers thedownlink data, which can save power of the user equipment.

FIG. 4 is a schematic flowchart of a method 400 for transmitting dataaccording to an embodiment of the present invention. As shown in FIG. 4,the method 400 may include:

S410: After receiving a first message sent by a user equipment,determine whether first indication information is stored, where thefirst indication information indicates that a server buffers downlinkdata to be sent to the user equipment.

S420: When determining that the first indication information is stored,determine whether a data volume of the downlink data is within a bearingrange of a second message, where the first indication informationfurther indicates the data volume of the downlink data.

S430: When the data volume of the downlink data is within the bearingrange of the second message, acquire the downlink data from the server,and send a second message carrying the downlink data to the userequipment, so that the user equipment acquires the downlink data fromthe second message carrying the downlink data.

Specifically, after receiving the first message, for example, a TAU/RAUrequest message, an attach request message, or a service requestmessage, sent by the user equipment, the core network control entity(for example, an SGSN or an MME) may check whether the first indicationinformation indicating that the server buffers the downlink data to besent to the user equipment is stored in the core network control entity;when determining that the first indication information is stored andthat the first indication information further indicates the data volumeof the downlink data, the core network control entity may determinewhether the data volume of the downlink data that is buffered in theserver and is to be sent to the current time is within a data bearingrange of the second message; and when the data volume of the downlinkdata that is buffered in the server and is to be sent to the currenttime is within the range of the data bearing range of the secondmessage, the core network control entity may acquire, from the server,the downlink data that is buffered in the server and is to be sent tothe user equipment, and then sends the second message carrying thedownlink data to the user equipment, so that the user equipment mayacquire the downlink data from the second message after receiving thesecond message that carries the downlink data and is sent by the corenetwork control entity.

In the embodiment of the present invention, the method 400 may furtherinclude:

when the data volume of the downlink data is not within the bearingrange of the second message, sending a second message including thefirst indication information or second indication information to theuser equipment, and sending a third message to the server, where thesecond indication information indicates that there is downlink data tobe sent to the user equipment, and the third message is used to instructthe server to send the downlink data to the user equipment, so that theuser equipment remains in a communication-capable state according to thefirst indication information or the second indication information, so asto wait to receive the downlink data sent by the server.

Therefore, in the embodiment of the present invention, the core networkcontrol entity may use non-access stratum (NAS) signaling, for example,a TAU/RAU response message or an attach accept message, to directlysend, to the user equipment, the downlink data that is buffered in theserver and is to be sent to the user equipment, which can reduce waitingtime of the user equipment, a paging process for sending data, and auser plane establishing process, and can achieve a power saving effectand save network resources.

FIG. 5 is a schematic flowchart of another method 500 for transmittingdata according to an embodiment of the present invention. The method 500is executed by a server, for example, an SCS or an MTC SERVER. Themethod 500 may include:

S510: Send first indication information to a core network controlentity, where the first indication information indicates that the serverbuffers downlink data to be sent to a user equipment and indicates adata volume of the downlink data, so that the core network controlentity stores the first indication information.

S520: When receiving a request for acquiring the downlink data, wherethe request is sent by the core network control entity after the corenetwork control entity receives a first message sent by the userequipment and when the core network control entity determines, accordingto the first indication information, that the data volume of thedownlink data is within a bearing range of a second message, send thesecond message carrying the downlink data to the core network controlentity, so that the core network control entity sends the second messagecarrying the downlink data to the user equipment.

In the embodiment of the present invention, the method 500 may furtherinclude:

when the third message is received, sending the downlink data to theuser equipment, where the third message is sent by the core networkcontrol entity after the core network control entity receives a firstmessage sent by the user equipment and when the core network controlentity determines, according to the first indication information, thatthe data volume of the downlink data is beyond a bearing range of asecond message, and the third message is used to request the server tosend the downlink data to the user equipment.

In the embodiment of the present invention, the method 500 may include:

when determining that a validity period of the downlink data expires,sending a fifth message to the core network control entity, where thefifth message is used to instruct the core network control entity todelete the first indication information.

Alternatively, in the embodiment of the present invention, the firstindication information is further used to indicate a validity period ofthe downlink data, so that the core network control entity deletes thefirst indication information when determining, according to the firstindication information, that the validity period of the downlink dataexpires.

Therefore, according to the method in the embodiment of the presentinvention, the first indication information is sent to the core networkcontrol entity. The first indication information indicates that theserver buffers the downlink data to be sent to the user equipment andindicates the data volume of the downlink data, so that the core networkcontrol entity stores the first indication information that is used todetermine whether the data volume of the downlink data is within thebearing range of the second message after the core network controlentity receives the first message sent by the user equipment. When thedownlink data volume is within the bearing range of the second message,the request for acquiring the downlink data is sent to the server. Afterreceiving the request that is for acquiring the downlink data and sentby the core network control entity, the server sends the downlink datato the core network control entity according to the request for thedownlink data, so that the core network control entity may usenon-access stratum (NAS) signaling, for example, a TAU/RAU responsemessage or an attach accept message, to directly send, to the userequipment, the downlink data that is buffered in the server and is to besent to the user equipment, which can reduce waiting time of the userequipment, a paging process for sending data, and a user planeestablishing process, and can achieve a power saving effect and savenetwork resources.

The embodiment of the present invention further provides another methodfor transmitting data, where the method may include:

after receiving uplink data sent by a user equipment, determiningwhether downlink data to be sent to the user equipment is buffered; and

when it is determined that the downlink data to be sent to the userequipment is buffered, sending the downlink data to the user equipment.

Specifically, when the user equipment initiates a service request to theserver, the uplink data may be sent to the server by using a servicerequest process to activate a PDP context or bearer; after receiving theuplink data sent by the user equipment, the server determines whetherthe downlink data to be sent to the user equipment is buffered, then theserver may send, to the user equipment, the downlink data that isbuffered and is to be sent to the user equipment, where the server maysend the downlink data buffered for the user equipment to the userequipment by using an established PDP context or bearer.

Therefore, in the method for transmitting data according to theembodiment of the present invention, a probability of transmittingbuffered data by the server is increased, in addition to that an effectof saving power of the user equipment can be achieved.

The foregoing already describes, with reference to FIG. 1 to FIG. 5, themethods for transmitting data according to the embodiments of thepresent invention separately from a core network control entity side, auser equipment side, and a server side. The following describes, withreference to FIG. 6A to FIG. 9B in an interworking manner, methods fortransmitting data according to the embodiments of the present invention.However, it should be understood that, the following embodiments aremerely intended to describe the present invention more clearly, andshould not constitute any limitations on the present invention.

FIG. 6A and FIG. 6B are a schematic flowchart of a method 600 fortransmitting data according to an embodiment of the present invention.As shown in FIG. 6A and FIG. 6B, the method 600 includes:

S601: A server (for example, an SCS or an MTC SERVER) has downlink datato be sent to a user equipment, and the server buffers correspondingdownlink data because current time is beyond a range of time in whichthe server is allowed to send data to the user equipment.

S602: The server sends data buffering indication information to a corenetwork control entity (for example, an MME or an SGSN) to which theuser equipment is currently attached, where the data bufferingindication information indicates that the server buffers the downlinkdata to be sent to the user equipment. The data buffering indicationinformation may be sent to the core network control entity (an SGSN oran MME) by using a Machine Type Communication Interworking Function(MTC-IWF) entity. The MTC-IWF determines, by querying a home subscriberserver (HSS), the core network control entity to which the userequipment is currently attached. After receiving the data bufferingindication information sent by the server, the core network controlentity may set first indication information that is used to indicatethat the server has the downlink data to be sent to the user equipment.

S603: The user equipment initiates a TAU/RAU process, and the userequipment sends a TAU/RAU request to the core network control entity.

S604: Execute other normal procedures of the TAU/RAU process, for whichreference may be made to the conventional art, and details are notrepeatedly described herein.

S605: Before sending a TAU/RAU accept message to the user equipment, thecore network control entity determines whether the first indicationinformation indicating that the server buffers the downlink data to besent to the user equipment is set. When it is determined that the firstindication information is set, S606 a to S608 a or S606 b to S609 b maybe executed; and when it is determined that the first indicationinformation is not set, S611 to S615 may be executed. Optionally, whenthe user equipment is a time-controlled device, before determiningwhether the first indication information is set, the core networkcontrol entity may further check, according to subscription data of theuser equipment, whether current time is allowed communication time forthe user equipment; and only when the current time belongs to a range ofallowed communication time, determines whether the first indicationinformation is set; otherwise, a subsequent process is not executed, anda normal procedure of the TAU/RAU process is executed.

S606 a: When determining that the first indication information is set,the core network control entity may forward the first indicationinformation to the user equipment by using the TAU/RAU accept message,or may generate second indication information indicating that there isdownlink data to be sent to the user equipment and send the secondindication information to the user equipment by using the TAU/RAU acceptmessage, where an identity of the server may be included in the TAU/RAUaccept message. In addition, the core network control entity instructsthe server to send the downlink data buffered for the user equipment tothe user equipment.

S607 a: After receiving the TAU/RAU accept message carrying the firstindication information or the second indication information, the userequipment remains in a communication-capable state, so as to wait forthe server to send the downlink data.

S608 a: The server sends the downlink data according to a normalprocedure, for which reference may be made to the conventional art, anddetails are not repeatedly described herein.

S606 a to S608 a are an implementation manner of a subsequent procedureof the method for transmitting data according to the embodiment of thepresent invention in a case in which the core network control entitydetermines that the first indication information is set in the corenetwork control entity, and S606 b to S610 b are another implementationmanner.

S606 b: When determining that the first indication information is set,the core network control entity may forward the first indicationinformation to the user equipment by using the TAU/RAU accept message,or may generate second indication information indicating that there isdownlink data to be sent to the user equipment and send the secondindication information to the user equipment by using the TAU/RAU acceptmessage, where an identity of the server may be included in the TAU/RAUaccept message. In addition, the core network control entity instructsthe server to send, to the user equipment, the downlink data that isbuffered and is to be sent to the user equipment.

S607 b: After receiving the TAU/RAU accept message carrying the firstindication information or the second indication information, the userequipment remains in a communication state, and keeps an established RRCconnection unreleased, that is, may not start a timer T3440 or T3340specified in an existing standard.

S608 b: The core network control entity receives a downlink datanotification or the downlink data sent by the server.

S609 b: After receiving the downlink data notification or downlink datasent by the server, the core network control entity establishes acorresponding radio bearer for a data packet that needs to betransmitted. Specifically, the core network control entity may directlyrequire an RAN side network element (an eNodeB or an RNC) to establishan E-RAB corresponding to a bearer for transmitting a corresponding datapacket or establish an RAB corresponding to a PDP context fortransmitting a corresponding data packet. For example, for an SAEnetwork, an MME sends an initial context setup message to an eNodeBaccording to an EPS bearer ID in the received downlink datanotification, so as to establish a corresponding E-RAB (radio bearer andS1 bearer); for another example, for a GPRS network, an SGSN sends aradio access bearer assignment message to an RNC, so as to establish acorresponding RAB (a user plane between the user equipment, the RNC, andthe SGSN). The execution process does not affect other bearer or PDPcontext information on the user equipment and the network side.

S610 b: The downlink data may be sent to the user equipment by a corenetwork by using the established bearer.

The following describes, with reference to S611 to S615, a subsequentexecution procedure of the method for transmitting data according to theembodiment of the present invention in a case in which the core networkcontrol entity determines that the first indication information is notset in the core network control entity.

S611: After determining that the first indication information is notset, the core network control entity generates third indicationinformation and sends the third indication information to the userequipment by using a TAU/RAU accept message, where the third indicationinformation indicates that there is no data to be sent to the userequipment.

S612: The core network control entity sends a user equipment contextrelease command to an RAN side network element.

S613: The RAN side network element releases the RRC connection to theuser equipment.

S614: The RAN side network element sends a user equipment contextrelease complete message.

S615: The user equipment disables a receiver or enters a power savingmode or shuts down, so as to save power.

In the embodiment of the present invention, if the data buffered in theserver has a validity period and if the data expires but the corenetwork control entity still stores the first indication information,the following two manners may be used for processing:

The server may send a message to the core network control entity toinstruct the core network control entity to delete the first indicationinformation that is stored in the core network control entity andindicates that the server buffers the downlink data to be sent to theuser equipment. Similarly, the instruction message is initiated by theserver and is sent, by using the MTC-IWF, to the core network controlentity to which the user equipment is currently attached. Then, the corenetwork control entity may delete the first indication informationaccording to the instruction of the server.

Alternatively, the server sends the validity period of the downlink datato be sent to the user equipment to the core network control entityalong with the first indication information. When the validity periodexpires but corresponding data is not sent yet, the core network controlentity deletes the stored first indication information.

It should be also understood that, in the embodiment of the presentinvention, in a case in which the core network control entitydetermines, in S605, that the first indication information is set in thecore network control entity, a subsequent execution procedure may alsobe implemented in another manner, in addition to the manner of S606 a toS608 a or the manner of S606 b to S610 b. The following introduces twospecific implementation manners.

Manner 1: The core network control entity retains a signaling connectionto the user equipment after sending, in S606 a to the user equipment,the TAU/RAU accept message including the first indication information orthe second indication information, and establishes a user plane beareror PDP context at the same time when sending, to the user equipment, theTAU/RAU accept message including the first indication information or thesecond indication information. Specifically, when returning, to the userequipment, the TAU/RAU accept message carrying the first indicationinformation or the second indication information, the core networkcontrol entity simultaneously executes a process of establishing E-RABsof all bearers or RABs of all PDP contexts, for example, for an SAEnetwork, it refers to establishing of radio bearers that are between theuser equipment and an eNodeB and are corresponding to all bearers, andestablishing of an S1 user plane connection between the eNodeB and anSGW; and for a UMTS network, it refers to establishing of radio bearersthat are between the user equipment and an RNC and are corresponding toall PDP contexts, and establishing of an Iu user plane connectionbetween the RNC and an SGSN. For a bearer for which no E-RAB/RAB issuccessfully established, the user equipment and the network release thebearer or the PDP context. After the eNodeB/RNC finishes establishingthe E-RAB/RAB, the core network control entity instructs the server tosend, to the user equipment, the downlink data that is buffered and isto be sent to the user equipment, and the server sends correspondingdata to the user equipment according to the instruction of the corenetwork control entity.

Manner 2: When a current access network of the user equipment is a GPRSnetwork, if the current user equipment has no PDP context information,after receiving the TAU/RAU accept message carrying the first indicationinformation or the second indication information, the user equipmentinitiates a process of activating a PDP context, so as to establish aPDP context. After establishing of the PDP context is complete, that is,an SGSN receives an active PDP context accept message sent by the userequipment, the SGSN instructs the server to send, to the user equipment,the downlink data that is buffered and is to be sent to the userequipment, and the server sends corresponding data to the user equipmentaccording to the instruction of the core network control entity. Data issent to the user equipment by using the established PDP context. Aparameter used by the user equipment to initiate the process ofactivating the PDP context may be preconfigured on the user equipment.

It should be also understood that the process described in the method600 for transmitting data in the embodiment of the present invention isalso applicable to an attach process of the user equipment, that is,after learning, by using an attach message, that the user equipment isalready online or already enables a receiver, the core network controlentity triggers the server to send the downlink data. This manner may beused in a case in which a user equipment is attached to a network againafter being detached from the network. In this manner, a probability oftriggering a server to send downlink data is increased, and in addition,an effect of saving power of the user equipment can be achieved.

For example, for a UMTS attach process, after receiving an attachrequest message from the user equipment, an SGSN determines whether thefirst indication information is stored. If the first indicationinformation is stored, the SGSN may carry the first indicationinformation or the second indication information in an attach acceptmessage. After receiving the attach accept message that carries thefirst indication information or the second indication information and issent by the SGSN, the user equipment remains in a communication-capablestate, or further keeps an RRC connection unreleased, and the SGSNtriggers the server to send downlink data to the user equipment. If thefirst indication information is not set, the SGSN may carry the thirdindication information in the attach accept message. After receiving theattach accept message carrying the third indication informationindicating that there is no data to be sent to the user equipment, theuser equipment disables the receiver or enters the power saving mode orshuts down. A specific procedure is consistent with the procedure of themethod 600 for transmitting data in the foregoing embodiment. Forbrevity, details are not repeatedly described herein.

For another example, for a 4G attach process, after receiving an attachrequest message from the user equipment, an MME determines whether thefirst indication information is set. If the first indication informationis set, the MME may add the first indication information or the secondindication information to an attach accept message. After receiving theattach accept message that carries the first indication information orthe second indication information and is sent by the MME, the userequipment keeps the receiver enabled, or further keeps an RRC connectionunreleased and keeps an E-RAB unreleased, and waits for the server tosend downlink data, and the MME triggers the server to send downlinkdata to the user equipment. If the first indication information is notstored, the third indication information indicating that there is nodata to be sent to the user equipment may be carried in the attachaccept message. After receiving the attach accept message carrying thethird indication information, the user equipment disables the receiveror enters the power saving mode or shuts down. A specific procedure isconsistent with the procedure of the method 600 in the foregoingembodiment. For brevity, details are not repeatedly described herein.

The embodiment of the present invention may also be applied to ascenario in which a core network control entity (MME or SGSN) serving auser equipment changes. A specific implementation manner is similar tothe method 600, except that when the server sends the first indicationinformation to a source core network control entity in S602 and the corenetwork control entity changes, after the user equipment sends a TAU/RAUrequest message to a new core network control entity in S603, the newcore network control entity needs to acquire information about the userequipment from the source core network control entity, and the sourcecore network control entity returns the information about the userequipment; and when the first indication information indicating that theserver buffers the downlink data to be sent to the user equipment isincluded in the information about the user equipment, the new corenetwork control entity acquires and sets the first indicationinformation. Other procedures are consistent with those of the method600. For brevity, details are not repeatedly described herein.

FIG. 7 is a schematic flowchart of a method 700 for transmitting dataaccording to an embodiment of the present invention. As shown in FIG. 7,the method 700 may include:

S701: A server (for example, an SCS or an MTC SERVER) has downlink datato be sent to a user equipment, and the server buffers correspondingdownlink data because current time is beyond a range of time in whichthe server is allowed to send data to the user equipment.

S702: The server sends first indication information (namely, the databuffering indication information described above) to a core networkcontrol entity to which the user equipment is currently attached, wherethe first indication information indicates that the server buffers thedownlink data to be sent to the user equipment, and the first indicationinformation further indicates a volume of the buffered data to be sentto the user equipment. In the embodiment of the present invention, thedata buffering indication information described above is the firstindication information described herein, which means that the corenetwork control entity directly stores the data buffering indicationinformation sent by the server as the first indication information.

S703: The user equipment starts to execute a TAU/RAU process and send aTAU/RAU request message to the core network control entity.

S704: After receiving the TAU/RAU request message sent by the userequipment, the core network control entity checks whether the firstindication information indicating that the server buffers the downlinkdata to be sent to the user equipment is stored. If the first indicationinformation is stored, the core network control entity further checkswhether the data volume of the downlink data that is buffered in theserver and is to be sent to the user equipment conforms to a volume ofdata transferred by using an NAS message (a TAU/RAU accept message), andif yes, S705 to S707 are executed, and if not, reference may be made tothe method 600 to execute a subsequent procedure; and if the corenetwork control entity determines that the first indication informationis not stored in the core network control entity, S708 and S709 areexecuted.

S705: The core network control entity decides to use a solution ofsending, to the user equipment by using an NAS message, the downlinkdata that is buffered in the server and is to be sent to the userequipment. First, the core network control entity sends instructioninformation to the server to instruct the server to send, to the corenetwork control entity, the buffered downlink data to be sent to theuser equipment, where the server may send, to the core network controlentity by using a control plane response message, the buffered downlinkdata to be sent to the user equipment. For a UMTS network, afterreceiving the instruction information of the core network controlentity, the server may also send, to the core network control entity byusing a user plane, the buffered downlink data to be sent to the userequipment.

S706: The core network control entity executes other steps of theTAU/RAU process, where S705 and S706 may be executed simultaneously.

S707: The core network control entity returns a TAU/RAU accept messageto the user equipment and adds the downlink data to be sent to the userequipment to the TAU/RAU accept message. In this way, the downlink datamay be sent to the user equipment by using NAS signaling (a TAU/RAUaccept response message).

S708: If the first indication information indicating that the serverbuffers the downlink data to be sent to the user equipment is not storedin the core network control entity, the core network control entityexecutes other steps of TAU/RAU according to a normal procedure.

S709: The core network control entity generates third indicationinformation indicating that there is no data to be sent to the userequipment, and sends the third indication information to the userequipment by using a TAU/RAU accept message. After receiving the TAU/RAUaccept message that carries the third indication information and is sentby the core network control entity, the user equipment disables areceiver or enters a power saving mode or shuts down, so as to achieve apower saving effect.

It should be understood that, the method 700 for transmitting dataaccording to the embodiment of the present invention may also be used ina process in which a user equipment attaches to a network again afterdetaching from the network, that is, after learning, by using an attachmessage, that the user equipment is already online or already enables areceiver, the core network control entity (an MME or an SGSN) determineswhether there is downlink data to be sent to the user equipment, and ifthere is downlink data to be sent to the user equipment, acquires thedownlink data from the server, uses an attach accept message to carrythe downlink data, and sends the downlink data to the user equipment.For other steps, reference may be made to the method 700. For brevity,details are not repeatedly described herein.

FIG. 8 is a schematic flowchart of a method 800 for transmitting dataaccording to an embodiment of the present invention. As shown in FIG. 8,the method 800 may include:

S801: A server (for example, an SCS or an MTC SERVER) has downlink datato be sent to a user equipment, and the server buffers correspondingdownlink data because current time is beyond a range of time in whichthe server is allowed to send data to the user equipment.

S802: The server sends data buffering indication information to a corenetwork control entity to which the user equipment is currentlyattached, where the data buffering indication information indicates thatthe server buffers the downlink data to be sent to the user equipment.After receiving the data buffering indication information sent by theserver, the core network control entity may set first indicationinformation that is used to indicate that the server buffers thedownlink data to be sent to the user equipment.

S803: When having data to send, the user equipment initiates a servicerequest, where the service request may be sent to the core networkcontrol entity by using an RAN entity.

S804: Execute other steps of a service request process, so as toactivate a PDP context, a bearer.

S805: The core network control entity checks whether the firstindication information indicating that the server buffers the downlinkdata to be sent to the user equipment is set.

S806: If the first indication information is set, the first indicationinformation may be sent to the user equipment by using a direct transfermessage, or second indication information indicating that the downlinkdata is to be sent to the user equipment may also be generated, and thesecond indication information may be sent to the user equipment by usinga direct transfer message. In particular, for a UMTS network, in a casein which an objective of the service request is to transmit data, thefirst indication information or the second indication information may besent to the user equipment by using a service accept message. In thisway, S805 and S806 may be integrated into S804 for implementation.

After receiving the indication information, the user equipment does notrelease an RRC connection and the PDP context or the bearer within aspecified period of time. The specified period of time does not conflictwith a service process, that is, the user equipment does not initiate aPDP context or bearer release process when the specified period of timeexpires but the service process does not end.

S807: The core network control entity instructs the server to send, tothe user equipment, the buffered downlink data to be sent to the userequipment, where S806 and S807 may be executed simultaneously, or S807may be first executed, and then S806 is executed, which depends on aspecific case, and is not limited in the embodiment of the presentinvention.

S808: The server sends the downlink data buffered for the user equipmentto the user equipment, and the core network control entity deletes thestored first indication information indicating that the server buffersthe downlink data to be sent to the user equipment.

The following describes, with reference to S809 to S812, a method fortransmitting data according to another implementation manner of thepresent invention.

S809: After activating the PDP context or the bearer in the servicerequest process, the user equipment may send uplink data to the server.

S810: After receiving the uplink data sent by the user equipment, theserver determines whether the downlink data to be sent to the userequipment is buffered, and if the downlink data to be sent to the userequipment is buffered, the server sends, to the user equipment, thebuffered downlink data to be sent to the user equipment, where thedownlink data may be transmitted by using the established PDP context orbearer on a network.

S811: The server sends, to the user equipment, the buffered downlinkdata to be sent to the user equipment.

S812: The server instructs the core network control entity to delete thestored first indication information, and the core network control entityis a core network control entity currently serving the user equipment.

FIG. 9A and FIG. 9B are a schematic flowchart of a method 900 fortransmitting data according to an embodiment of the present invention.As shown in FIG. 9A and FIG. 9B, the method 900 includes:

S901: A server (for example, an SCS or an MTC SERVER) has downlink datato be sent to a user equipment, and the server buffers correspondingdownlink data because current time is beyond a range of time in whichthe server is allowed to send data to the user equipment.

S902: When buffering the downlink data, the server simultaneously sendsa registration request message (namely, the user equipment reachabilitynotification request message described above) to a home subscriberserver (HSS) or home location register (HLR) to which the user equipmentbelongs, so as to acquire a user equipment reachability notificationmessage, where the registration request message may be sent to the HSSor the HLR by using an MTC-IWF. The registration request message atleast includes address information of the server and identityinformation of the user equipment, and may further include a validityperiod of to-be-sent data.

S903: According to the registration request message of the server, theHSS or the HLR stores the address information of the server and theidentity information of the user equipment, and if the registrationrequest message includes a validity period of to-be-sent data, mayfurther store the validity period of the to-be-sent data, and at thesame time sets a URRP (UE Reachability Request Parameter) user equipmentreachability request parameter identifier, indicating that userequipment reachability information needs to be learnt and alsoindicating that there is downlink data to be sent to the user equipment.That the user equipment subsequently sends a TAU/RAU request or sendsuplink data indicate that the user equipment is reachable. Thisspecification uses sending of a TAU/RAU request message as an examplefor description.

S904: The HSS or the HLR sends, according to the registration requestmessage of the server, a user equipment reachability notificationrequest message to a core network control entity to which the userequipment belongs, where the user equipment reachability notificationrequest message may include the identity information of the userequipment.

S905: After receiving the user equipment reachability notificationrequest message, the core network control entity sets a URRP (namely,the first indication information described above), which may indicatethat the server has the downlink data to be sent to the user equipmentand may also indicate that when the UE is reachable, the core networkcontrol entity needs to notify the HSS or the HLR.

When the registration request message includes a validity period ofto-be-sent data, the HSS or the HLR may store the validity period of theto-be-sent data. If the validity period of the to-be-sent data expiresand the data is not sent yet, the HSS or the HLR may delete the URRPidentifier, and instruct the core network control entity to delete thestored URRP identifier.

S906: The user equipment sends a TAU/RAU request to the core networkcontrol entity.

S907: The core network control entity executes a normal procedure of aTAU/RAU process.

S908: The core network control entity checks whether the URRP identifieris set. If the URRP is set, S909 to S916 are executed; otherwise, S917to S920 are executed.

For a time-controlled user equipment, the core network control entityneeds to further check whether current time is allowed communicationtime for the user equipment. If the current time is within a range ofallowed communication time, S909 to S916 are executed; otherwise, theTAU/RAU process is implemented according to the conventional art.

S909: The core network control entity returns a TAU/RAU accept message.

S910: The core network control entity keeps a signaling connection tothe user equipment unreleased, that is, does not send an S1 releaserequest or Iu release request message to an RAN side entity.

S911: The core network control entity sends, according to a detectedURRP, to the user equipment, indication information (namely, the secondindication information described above) indicating that there isdownlink data to be sent to the user equipment, so that the userequipment keeps the signaling connection unreleased. The indicationinformation may be carried in a new NAS message (for example, a downlinkNAS transport message) and sent to the UE by using the new NAS message.

Certainly, the indication information may also be carried in the TAU/RAUaccept message in S909 and sent to the user equipment.

S912: After receiving the indication information that is sent by thecore network control entity and indicates that there is downlink data tobe sent to the user equipment, the user equipment keeps the signalingconnection unreleased, that is, does not start a timer T3440/T3340; andif the timer T3440/T3340 has been started after the user equipmentreceives the TAU/RAU accept message, the user equipment deletes thetimer T3440 after receiving the indication information.

S913: The core network control entity sends the user equipmentreachability notification message to the HSS or the HLR according to thedetected identifier, namely, the URRP, so as to notify that the userequipment is reachable. S911 and S913 may be executed simultaneously,and no sequence is set.

S914: The HSS or the HLR sends the user equipment reachabilitynotification message to a specified server according to informationrelated to the UE and stored in the HSS or HLR, so as to notify that theuser equipment is reachable, and trigger the server to send the downlinkdata stored in server to the user equipment.

S915: After determining that the URRP identifier exists, the corenetwork control entity activates E-RABs/RABs that are on a radio sideand are corresponding to all bearers or PDP contexts, that is, executesa process of establishing E-RABs/RABs of all activated bearers/PDPcontexts. For a SAE network, it refers to establishing of a radio bearerbetween the UE and an eNodeB and establishing of an S1 user planeconnection between the eNodeB and an SGW; and for a UMTS network, itrefers to establishing of a radio bearer between the UE and an RNC andestablishing of an Iu user plane connection between the RNC and an SGSN.For a bearer for which no E-RAB/RAB is successfully established, the UEand the network release the bearer or the PDP context. This step is anoptional step. If this step is executed, S913 a and S914 are executedafter this step. A process of establishing a user plane bearer may alsobe executed according to other manners described in other embodiments,and details are not repeatedly described herein.

S916: The server sends the stored downlink data to the user equipment.

S917: The core network control entity returns a TAU/RAU accept message.

The following describes, with reference to S917 to S922, a subsequentexecution procedure of the method 900 for transmitting data according tothe embodiment of the present invention when the core network controlentity determines that the server has no downlink data to be sent to theuser equipment.

S917: The core network control entity returns a TAU/RAU accept message.

S918: If the core network control entity does not store the URRPidentifier, the core network control entity sends, to the userequipment, third indication information indicating that the server hasno downlink data to be sent, where the third indication information maybe implemented in the following manners:

the third indication information is carried in a new NAS message, forexample, a downlink NAS transport message and sent to the UE; and

the indication information is carried in the TAU/RAU accept message inS917 and sent to the UE.

The third indication information is used to instruct the UE to enter apower saving state, that is, disable a receiver or enter another powersaving state or shut down, after the TAU/RAU process is implemented.

S919: The core network control entity initiates an S1 or Iu signalingconnection release process, and the RAN side entity initiates an RRCconnection release process.

S920: After releasing an RRC connection, the user equipment disables thereceiver or enters another power saving mode or shuts down according tothe third indication information received in S918.

It should be understood that, the foregoing description is merelyspecific embodiments of the present invention, and should not constituteany limitations on the present invention. For example, for the method900, S911 and S912 may not be executed, and the core network controlentity may choose, according to duration in which the user equipment canretain a signaling connection, whether to send, to the user equipment,the indication information indicating that the server has the downlinkdata to be sent to the user equipment. For example, if the duration inwhich the user equipment can retain a signaling connection is 11seconds, S911 and S912 may not be executed because 11 seconds is notless than a predetermined threshold of 10 seconds. The duration in whichthe user equipment can retain a signaling connection may be determinedaccording to UE subscription data, a network configuration, or a UEreport. If the core network control entity does not send the indicationinformation to the user equipment, the user equipment may retain thesignaling connection for a predetermined period of time, so as to waitto receive the downlink data sent by the server. The UE may enter anidle mode or a power saving state, or shut down after retaining thesignaling connection for the predetermined period of time, so as tofurther save power. For another example, in the method 900, whether theto-be-sent data expires is determined according to the validity period,of the downlink data, carried in the registration request message. Inthe method according to the embodiment of the present invention, thevalidity period of the downlink data may also not be carried in theregistration request message, and instead, the server directly sends auser equipment reachability notification cancellation message to the HSSor the HLR when determining that the validity period of the downlinkdata expires. After receiving the user equipment reachabilitynotification cancellation message sent by the server, the HSS or the HLRmay delete the URRP identifier stored in the HSS or the HLR, andinstruct the core network control entity to delete the stored URRPidentifier. In the embodiment of the present invention, when multipleservers need to send data to the user equipment, after receiving a userequipment reachability notification cancellation message sent by anyserver or determining that data to be sent by any server to the userequipment expires, the home subscriber server or the home locationregister may delete user equipment reachability-related information ofthe any server. After deleting all user equipment reachability-relatedinformation of the multiple servers, that is, there is no notificationrequest for user equipment reachability, the home subscriber server orthe home location register deletes the URRP identifier stored in thehome subscriber server or the home location register and instructs thecore network control entity to delete the stored URRP identifier.

It should be also understood that, sequence numbers of the processes inthe foregoing methods do not imply execution sequences. The executionsequences of the processes should be determined by functions andinternal logic, and should not constitute any limitation onimplementation processes of the embodiments of the present invention.

The foregoing already describes schematic flowcharts of the methods fortransmitting data according to the embodiments of the present inventionwith reference to FIG. 1 to FIG. 9B. The following describes apparatusesfor transmitting data according to the embodiments of the presentinvention with reference to FIG. 10 to FIG. 19, where the apparatusesinclude a core network control entity, a user equipment, and a server.

FIG. 10 is a schematic block diagram of a core network control entity1000 according to an embodiment of the present invention. As shown inFIG. 10, the core network control entity 1000 includes:

a first determining unit 1010, configured to: after receiving a firstmessage sent by a user equipment, determine whether first indicationinformation is set, where the first indication information indicatesthat a server buffers downlink data to be sent to the user equipment;and

a triggering unit 1020, configured to: when the first determining unitdetermines that the first indication information is set, trigger theserver that buffers the downlink data to send the downlink data to theuser equipment;

a retaining unit 1030, configured to: when the first determining unitdetermines that the first indication information is set, retain asignaling connection to the user equipment.

Therefore, after receiving the first message sent by the user equipment,the core network control entity according to the embodiment of thepresent invention determines whether the first indication information isset, where the first indication information indicates that the serverbuffers the downlink data to be sent to the user equipment, and retainsthe signaling connection to the user equipment when determining that thefirst indication information is set, which can reduce signalingconsumption in a process of sending downlink data, and avoid a processof disconnecting and reestablishing a signaling connection between auser equipment and a network entity, thereby avoiding frequent statuschanges of the user equipment and the network entity, and saving powerof the user equipment.

Optionally, the triggering unit 1020 is configured to:

send a downlink data delivery request message to the server that buffersthe downlink data, so as to trigger the server that buffers the downlinkdata to send the downlink data to the user equipment; or

the triggering unit 1020 is configured to:

send a first user equipment reachability notification message to a homesubscriber server or home location register to which the user equipmentbelongs, so that the home subscriber server or the home locationregister sends a second user equipment reachability notification messageto the server that buffers the downlink data, so as to trigger theserver that buffers the downlink data to send the downlink data to theuser equipment.

Optionally, the retaining unit 1030 is configured to:

send a second message including second indication information to theuser equipment, where the second indication information indicates thatthere is data to be sent to the user equipment, so as to retain thesignaling connection to the user equipment.

Optionally, the retaining unit 1030 is configured to:

when duration, preset for the user equipment, in which a signalingconnection can be retained is less than a predetermined threshold, sendthe second message to the user equipment.

Optionally, as shown in FIG. 11, the core network control entity 1000further includes:

a first sending unit 1040, configured to: when it is determined that thefirst indication information is not set, send a third message includingthird indication information to the user equipment, where the thirdindication information indicates that there is no downlink data to besent to the user equipment, so that the user equipment disables areceiver or enters a power saving mode or shuts down according to thethird indication information.

Optionally, the second indication information further includes addressinformation of the server.

Optionally, as shown in FIG. 11, the core network control entity 1000further includes:

a second determining unit 1050, configured to: when the user equipmentis a time-controlled user equipment, determine whether the current timeis within a range of allowed communication time, where

the first determining unit 1010 is configured to:

when the second determining unit 1050 determines that the current timeis within the range of allowed communication time of the user equipment,determine whether the first indication information is set.

Optionally, the core network control entity 1000 further includes:

a first receiving unit 1061, configured to receive a second userequipment reachability notification request message that is sent by thehome subscriber server or home location register to which the userequipment belongs after the home subscriber server or home locationregister receives a first user equipment reachability notificationrequest message, and a first setting unit 1062, configured to set thefirst indication information according to the second user equipmentreachability notification request message received by the firstreceiving unit; or includes:

a second receiving unit 1063, configured to receive data bufferingindication information sent by the server that buffers the downlinkdata, where the data buffering indication information indicates that theserver buffers the downlink data to be sent to the user equipment, and asecond setting unit 1064, configured to set the first indicationinformation according to the data buffering indication information.

Optionally, as shown in FIG. 11, the core network control entity 1000further includes:

a third receiving unit 1065, configured to receive a context responsemessage sent by a source core network control entity serving the userequipment; and

a third setting unit 1066, configured to: when the context responsemessage received by the third receiving unit includes the firstindication information, set the first indication information.

Optionally, as shown in FIG. 11, the core network control entity 1000further includes:

a first deleting unit 1071, configured to: when determining, accordingto the first indication information, that a validity period of thedownlink data expires, delete the first indication information, wherethe first indication information is further used to indicate thevalidity period of the downlink data, and the validity period, indicatedby the first indication information, of the downlink data is setaccording to a validity period, of the downlink data, carried in thedata buffering indication information sent by the server that buffersthe downlink data; or includes:

a fourth receiving unit 1072, configured to receive a fourth messagethat is sent, after a validity period of the downlink data expires, bythe server that buffers the downlink data, where the fourth message isused as an instruction to delete the first indication information, and asecond deleting unit 1073, configured to delete the first indicationinformation according to the fourth message received by the fourthreceiving unit; or includes:

a fifth receiving unit 1074, configured to receive a first userequipment reachability notification cancellation message sent by thehome subscriber server or home location register to which the userequipment belongs, and a third deleting unit 1075, configured to deletethe first indication information according to the first user equipmentreachability notification cancellation message received by the fifthreceiving unit 1074.

Optionally, the fifth receiving unit 1074 is configured to:

receive the first user equipment reachability notification cancellationmessage that is sent by the home subscriber server or the home locationregister according to a second user equipment reachability notificationcancellation message sent by the server that buffers the downlink dataof the user equipment; or is configured to:

receive the first user equipment reachability notification cancellationmessage that is sent by the home subscriber server or the home locationregister after the home subscriber server or the home location registerdetermines, according to the first user equipment reachabilitynotification request message, that the downlink data expires, where thefirst user equipment reachability notification request message carriesthe validity period of the downlink data.

Optionally, as shown in FIG. 11, the core network control entity 1000further includes:

an establishing unit 1080, configured to: after a downlink datanotification message or downlink data sent by the server that buffersthe downlink data is received, establish an evolved universalterrestrial radio access network radio access bearer corresponding to abearer for transmitting a corresponding data packet or establish a radioaccess bearer corresponding to a Packet Data Protocol context fortransmitting a corresponding data packet; or, configured to establish auser plane bearer or a Packet Data Protocol context.

FIG. 12 is a schematic block diagram of a core network control entity1100 according to an embodiment of the present invention. As shown inFIG. 12, the core network control entity 1100 includes:

a receiver 1110, configured to receive a first message sent by a userequipment; and

a processor 1120, configured to: after the receiver 1110 receives thefirst message sent by the user equipment, determine whether firstindication information is set, where the first indication informationindicates that a server buffers downlink data to be sent to the userequipment; and when determining that the first indication information isset, retain a signaling connection to the user equipment and trigger theserver that buffers the downlink data to send the downlink data to theuser equipment.

Therefore, after receiving the first message sent by the user equipment,the core network control entity in the embodiment of the presentinvention determines whether the first indication information is set,where the first indication information indicates that the server buffersthe downlink data to be sent to the user equipment, and retains thesignaling connection to the user equipment when determining that thefirst indication information is set, so that power of the user equipmentcan be saved.

Optionally, as shown in FIG. 13, the core network control entity 1100further includes a sender 1130, where the processor 1120 is configuredto instruct the sender 1130 to send a downlink data delivery requestmessage to the server that buffers the downlink data, so as to triggerthe server that buffers the downlink data to send the downlink data tothe user equipment; and the sender 1130 is configured to send, accordingto the instruction of the processor 1120, the downlink data deliveryrequest message to the server that buffers the downlink data, so as totrigger the server that buffers the downlink data to send the downlinkdata to the user equipment; or

the processor 1120 is configured to instruct the sender 1130 to send afirst user equipment reachability notification message to a homesubscriber server or home location register to which the user equipmentbelongs, so that the home subscriber server or the home locationregister sends a second user equipment reachability notification messageto the server that buffers the downlink data, and therefore the serverthat buffers the downlink data sends the downlink data to the userequipment; and the sender 1130 is configured to send, according to theinstruction of the processor 1120, the first user equipment reachabilitynotification message to the home subscriber server or home locationregister to which the user equipment belongs.

Optionally, as shown in FIG. 13, the core network control entity 1100further includes a sender 1130, where the processor 1120 is configuredto instruct the sender 1130 to send a second message including secondindication information to the user equipment, where the secondindication information indicates that there is data to be sent to theuser equipment, so as to retain a signaling connection to the userequipment; and the sender 1130 is configured to send, according to theinstruction of the processor 1120, the second message including thesecond indication information to the user equipment, where the secondindication information indicates that there is the data to be sent tothe user equipment, so as to retain the signaling connection to the userequipment.

Optionally, the processor 1120 is configured to: when determining thatduration, preset for the user equipment, in which a signaling connectioncan be retained is less than a predetermined threshold, instruct thesender 1130 to send the second message to the user equipment.

Optionally, as shown in FIG. 13, the core network control entity 1100further includes a sender 1130, where the processor is configured to:when determining that the first indication information is not set,instruct the sender 1130 to send a third message including thirdindication information to the user equipment, where the third indicationinformation indicates that there is no downlink data to be sent to theuser equipment, so that the user equipment disables a receiver or entersa power saving mode or shuts down according to the third indicationinformation; and the sender 1130 is configured to send, according to theinstruction of the processor 1120, the third message including the thirdindication information to the user equipment, where the third indicationinformation indicates that there is no downlink data to be sent to theuser equipment, so that the user equipment disables a receiver or entersa power saving mode or shuts down according to the third indicationinformation.

Optionally, the second indication information further includes addressinformation of the server.

Optionally, the processor 1120 is further configured to: when the userequipment is a time-controlled user equipment, determine whether thecurrent time is within a range of allowed communication time; and isconfigured to: when determining that the current time is within therange of allowed communication time of the user equipment, determinewhether the first indication information is set.

Optionally, the receiver 1110 is further configured to receive a seconduser equipment reachability notification request message that is sent bythe home subscriber server or home location register to which the userequipment belongs after the home subscriber server or home locationregister receives a first user equipment reachability notificationrequest message, and the processor 1120 is further configured to set thefirst indication information according to the second user equipmentreachability notification request message received by the receiver 1110;or

the receiver 1110 is further configured to receive data bufferingindication information sent by the server that buffers the downlinkdata, where the data buffering indication information indicates that theserver buffers the downlink data to be sent to the user equipment, andthe processor 1120 is further configured to set the first indicationinformation according to the data buffering indication information.

Optionally, the receiver 1110 is further configured to receive a contextresponse message sent by a source core network control entity servingthe user equipment, and the processor 1120 is further configured to setthe first indication information when the context response messagereceived by the receiver 1110 includes the first indication information.

Optionally, the processor 1120 is further configured to: whendetermining, according to the first indication information, that avalidity period of the downlink data expires, delete the firstindication information, where the first indication information isfurther used to indicate the validity period of the downlink data, andthe validity period, indicated by the first indication information, ofthe downlink data is set according to a validity period, of the downlinkdata, carried in the data buffering indication information sent by theserver that buffers the downlink data.

Optionally, the receiver 1110 is further configured to receive a fourthmessage that is sent, after a validity period of the downlink dataexpires, by the server that buffers the downlink data, where the fourthmessage is used as an instruction to delete the first indicationinformation, and the processor 1120 is further configured to delete thefirst indication information according to the fourth message received bythe receiver 1110.

Optionally, the receiver 1110 is further configured to receive a firstuser equipment reachability notification cancellation message sent bythe home subscriber server or home location register to which the userequipment belongs, and the processor 1120 is further configured todelete the first indication information according to the first userequipment reachability notification cancellation message received by thereceiver 1110.

Optionally, the receiver 1110 is configured to:

receive the first user equipment reachability notification cancellationmessage that is sent by the home subscriber server or the home locationregister according to a second user equipment reachability notificationcancellation message sent by the server that buffers the downlink dataof the user equipment; or is configured to:

receive the first user equipment reachability notification cancellationmessage that is sent by the home subscriber server or the home locationregister after the home subscriber server or the home location registerdetermines, according to the first user equipment reachabilitynotification request message, that the downlink data expires, where thefirst user equipment reachability notification request message carriesthe validity period of the downlink data.

Optionally, the receiver 1110 is further configured to receive adownlink data notification message or downlink data sent by the serverthat buffers the downlink data, and the processor 1120 is furtherconfigured to: after the receiver 1110 receives the downlink datanotification message or downlink data sent by the server that buffersthe downlink data, establish an evolved universal terrestrial radioaccess network radio access bearer corresponding to a bearer fortransmitting a corresponding data packet or establish a radio accessbearer corresponding to a Packet Data Protocol context for transmittinga corresponding data packet.

Optionally, the processor 1120 is further configured to establish a userplane bearer or a Packet Data Protocol context.

Therefore, after receiving the first message sent by the user equipment,the core network control entity in the embodiment of the presentinvention determines whether the first indication information is set,where the first indication information indicates that the server buffersthe downlink data to be sent to the user equipment, and retains thesignaling connection to the user equipment when determining that thefirst indication information is set, which can reduce signalingconsumption in a process of sending downlink data, and avoid a processof disconnecting and reestablishing a signaling connection between auser equipment and a network entity, thereby avoiding frequent statuschanges of the user equipment and the network entity, and saving powerof the user equipment. Further, when determining that the server has thedownlink data to be sent to the user equipment, the core network controlentity establishes a bearer required for sending the downlink data,thereby saving time required for transmitting the downlink data.Further, in the embodiment of the present invention, only after it isdetermined that the current time is within the range of allowedcommunication time of the user equipment, it is determined whether thefirst indication information is set, which reduces network load.Further, in the embodiment of the present invention, the first messagemay be a TAU/RAU request message, an attach request message, or aservice request message, so that chances for the server to send buffereddownlink data to the user equipment can be increased, which preventsdata from becoming invalid or being deleted.

FIG. 14 is a schematic block diagram of a user equipment 1200 accordingto an embodiment of the present invention. As shown in FIG. 14, the userequipment 1200 includes:

a sending unit 1210, configured to send a first message to a corenetwork control entity;

a power saving unit 1220, configured to: when receiving a third messagethat includes third indication information and is sent by the corenetwork control entity according to the first message, disable areceiver or enable the user equipment to enter a power saving mode orshut down, where the third indication information indicates that aserver has no downlink data to be sent to the user equipment.

Therefore, the user equipment according to the embodiment of the presentinvention sends the first message to the core network control entity,and after receiving the third message that includes the third indicationinformation and is sent by the core network control entity according tothe first message, disables the receiver or enters the power saving modeor shuts down, where the third indication information indicates thatthere is no downlink data to be sent to the user equipment, so thatpower of the user equipment can be saved.

Optionally, as shown in FIG. 15, the user equipment 1200 furtherincludes:

a retaining unit 1230, configured to: when receiving a second messagethat includes second indication information and is sent by the corenetwork control entity according to the first message, retain anestablished signaling connection, so as to wait to receive the downlinkdata, where the second indication information indicates that the serverhas downlink data to be sent to the user equipment.

Optionally, as shown in FIG. 15, when the user equipment 1200 includesthe retaining unit 1230, the user equipment further includes:

a determining unit 1240, configured to: when a current access network isa general packet radio service technology network, determine whether aPacket Data Protocol context is reserved; and

an initiating unit 1250, configured to: when no Packet Data Protocolcontext is reserved, initiate a Packet Data Protocol context process, soas to establish a Packet Data Protocol context.

Therefore, the user equipment according to the embodiment of the presentinvention sends the first message to the core network control entity;after receiving the third message that includes the third indicationinformation and is sent by the core network control entity according tothe first message, disables the receiver or enters the power saving modeor shuts down, where the third indication information indicates thatthere is no downlink data to be sent to the user equipment; and afterreceiving the second message that includes the second indicationinformation and is sent by the core network control entity according tothe first message, retains the established signaling connection, so asto wait to receive the downlink data, where the second indicationinformation indicates that there is downlink data to be sent to the userequipment, so that power of the user equipment can be saved.

FIG. 16 is a schematic block diagram of a user equipment 1300 accordingto an embodiment of the present invention. As shown in FIG. 16, the userequipment 1300 includes:

a sender 1310, configured to send a first message to a core networkcontrol entity;

a receiver 1320, configured to receive a third message that includesthird indication information and is sent by the core network controlentity according to the first message, where the third indicationinformation indicates that a server has no downlink data to be sent tothe user equipment; and

a processor 1330, configured to disable a receiver or enter a powersaving mode or power off the user equipment when the receiver 1320receives the third message.

Therefore, the user equipment according to the embodiment of the presentinvention sends the first message to the core network control entity,and after receiving the third message that includes the third indicationinformation and is sent by the core network control entity according tothe first message, disables the receiver or enters the power saving modeor shuts down, where the third indication information indicates thatthere is no downlink data to be sent to the user equipment, so thatpower of the user equipment can be saved.

Optionally, the receiver 1320 is further configured to receive a secondmessage that includes second indication information and is sent by thecore network control entity according to the first message, where thesecond indication information indicates that the server has downlinkdata to be sent to the user equipment.

The processor 1330 is further configured to retain an establishedsignaling connection when the receiver receives the second message, soas to wait to receive the downlink data.

Optionally, the processor 1330 is further configured to: when a currentaccess network is a general packet radio service technology network,determine whether a Packet Data Protocol context is reserved; and whenno Packet Data Protocol context is reserved, initiate a Packet DataProtocol context process, so as to establish a Packet Data Protocolcontext.

Therefore, the user equipment according to the embodiment of the presentinvention sends the first message to the core network control entity;after receiving the third message that includes the third indicationinformation and is sent by the core network control entity according tothe first message, disables the receiver or enters the power saving modeor shuts down, where the third indication information indicates thatthere is no downlink data to be sent to the user equipment; and afterreceiving the second message that includes the second indicationinformation and is sent by the core network control entity according tothe first message, retains the established signaling connection, so asto wait to receive the downlink data, where the second indicationinformation indicates that there is downlink data to be sent to the userequipment, so that power of the user equipment can be saved.

FIG. 17 is a schematic block diagram of a server 1400 according to anembodiment of the present invention. As shown in FIG. 17, the server1400 includes a first sending unit 1410, a receiving unit 1420, and asecond sending unit 1430, where

the first sending unit 1410 is configured to send a first user equipmentreachability notification request message to a home subscriber server orhome location register to which a user equipment belongs, so that thehome subscriber server or the home location register sends a second userequipment reachability notification request message to a core networkcontrol entity to which the user equipment belongs, and therefore thecore network control entity sets first indication information accordingto the second user equipment reachability notification request message,where the first indication information indicates that the server buffersdownlink data to be sent to the user equipment; the receiving unit 1420is configured to receive a second user equipment reachabilitynotification message that is sent by the home subscriber server or thehome location register after the home subscriber server or the homelocation register receives a first user equipment reachabilitynotification message that is sent by the core network control entityaccording to the first indication information; and the second sendingunit 1430 is configured to send the downlink data to the user equipment;or

the first sending unit 1410 is configured to send data bufferingindication information to a core network control entity to which a userequipment belongs, so that the core network control entity sets firstindication information according to the data buffering indicationinformation, where the data buffering indication information indicatesthat the server buffers downlink data to be sent to the user equipmentand the first indication information indicates that the server buffersthe downlink data to be sent to the user equipment; the receiving unit1420 is configured to receive a downlink data delivery request messagethat is sent by the core network control entity according to the firstindication information; and the second sending unit 1430 is configuredto send the downlink data to the user equipment.

Optionally, as shown in FIG. 18, the server 1400 further includes: athird sending unit 1440, configured to: when determining that thedownlink data expires, send a second user equipment reachabilitynotification cancellation message to the home subscriber server or thehome location register, so that the home subscriber server or the homelocation register sends a first user equipment reachability notificationcancellation message to the core network control entity, and thereforethe core network control entity deletes the first indication informationaccording to the first user equipment reachability notificationcancellation message.

Optionally, the first user equipment reachability notification requestmessage further includes a validity period of the downlink data, so thatthe home subscriber server sends a first user equipment reachabilitynotification cancellation message to the core network control entitywhen determining, according to the first user equipment reachabilitynotification request message, that the validity period of the downlinkdata expires, and therefore the core network control entity deletes thefirst indication information according to the first user equipmentreachability notification cancellation message.

Optionally, as shown in FIG. 18, the server 1400 further includes: afourth sending unit 1450, configured to: when determining that avalidity period of the downlink data expires, send a fourth message tothe core network control entity, where the fourth message is used toinstruct the core network control entity to delete the first indicationinformation.

Optionally, the data buffering indication information further includes avalidity period of the downlink data, so that the core network controlentity sets the first indication information that is further used toindicate the validity period of the downlink data, and deletes the firstindication information when the validity period of the downlink dataexpires.

Therefore, the server according to the embodiment of the presentinvention sends the first user equipment reachability notificationrequest message to the home subscriber server or the home locationregister, so that the home subscriber server or the home locationregister sends the second user equipment reachability notificationrequest message to the core network control entity, and therefore thecore network control entity sets the first indication informationaccording to the second user equipment reachability notification requestmessage, where the first indication information indicates that theserver buffers the downlink data to be sent to the user equipment, andthe server sends the downlink data to the user equipment when receivinga second user equipment reachability notification response message thatis sent by the home subscriber server or the home location registerafter the home subscriber server or the home location register receivesa first user equipment reachability notification response message thatis sent by the core network control entity according to the firstindication information; or sends the data buffering indicationinformation to the core network control entity, so that the core networkcontrol entity sets the first indication information according to thedata buffering indication information, where the data bufferingindication information indicates that the downlink data to be sent tothe user equipment is buffered and the first indication informationindicates that another entity has downlink data to be sent to the userequipment, and the another entity sends the downlink data to the userequipment when receiving a request message that is sent by the corenetwork control entity according to the first indication information andtriggers the downlink data, which can save power of the user equipment.

FIG. 19 is a schematic block diagram of a server 1500 according to anembodiment of the present invention. As shown in FIG. 19, the server1500 includes a processor 1510, a sender 1520, and a receiver 1530,where

the processor 1510 is configured to instruct the sender 1520 to send afirst user equipment reachability notification request message to a homesubscriber server or home location register to which a user equipmentbelongs, so that the home subscriber server or the home locationregister sends a second user equipment reachability notification requestmessage to a core network control entity to which the user equipmentbelongs, and therefore the core network control entity sets firstindication information according to the second user equipmentreachability notification request message, where the first indicationinformation indicates that the server buffers downlink data to be sentto the user equipment;

the sender 1520 is configured to send, according to the instruction ofthe processor 1510, the first user equipment reachability notificationrequest message to the home subscriber server or home location registerto which the user equipment belongs;

the receiver 1530 is configured to receive a second user equipmentreachability notification message that is sent by the home subscriberserver or the home location register after the home subscriber server orthe home location register receives a first user equipment reachabilitynotification message that is sent by the core network control entityaccording to the first indication information;

the processor 1510 is further configured to instruct, according to thesecond user equipment reachability notification message received by thereceiver, the sender 1520 to send the downlink data to the userequipment; and

the sender 1520 is further configured to send the downlink data to theuser equipment according to the instruction of the processor 1510.

Alternatively, the processor 1510 is configured to instruct the sender1520 to send data buffering indication information to a core networkcontrol entity to which a user equipment belongs, so that the corenetwork control entity sets first indication information according tothe data buffering indication information, where the data bufferingindication information indicates that the server buffers downlink datato be sent to the user equipment and the first indication informationindicates that the server buffers the downlink data to be sent to theuser equipment;

the sender 1520 is configured to send, according to the instruction ofthe processor 1510, the data buffering indication information to thecore network control entity to which the user equipment belongs;

the receiver 1530 is configured to receive a downlink data deliveryrequest message that is sent by the core network control entityaccording to the first indication information;

the processor 1510 is further configured to instruct, according to thedownlink data delivery request message received by the receiver 1530,the sender 1520 to send the downlink data to the user equipment; and

the sender 1520 is further configured to send the downlink data to theuser equipment according to the instruction of the processor 1510.

Optionally, the processor 1510 is further configured to: whendetermining that the downlink data expires, instruct the sender 1520 tosend a second user equipment reachability notification cancellationmessage to the home subscriber server or the home location register, sothat the home subscriber server or the home location register sends afirst user equipment reachability notification cancellation message tothe core network control entity, and therefore the core network controlentity deletes the first indication information according to the firstuser equipment reachability notification cancellation message; and

the sender 1520 is further configured to send the second user equipmentreachability notification cancellation message to the home subscriberserver or the home location register according to the instruction of theprocessor 1510.

Optionally, the first user equipment reachability notification requestmessage further includes a validity period of the downlink data, so thatthe home subscriber server sends a first user equipment reachabilitynotification cancellation message to the core network control entitywhen determining, according to the first user equipment reachabilitynotification request message, that the validity period of the downlinkdata expires, and therefore the core network control entity deletes thefirst indication information according to the first user equipmentreachability notification cancellation message.

Optionally, the processor 1510 is further configured to: whendetermining that a validity period of the downlink data expires,instruct the sender 1520 to send a fourth message to the core networkcontrol entity, where the fourth message is used to instruct the corenetwork control entity to delete the first indication information; and

the sender 1520 is further configured to send the fourth message to thecore network control entity according to the instruction of theprocessor.

Optionally, the data buffering indication information further includes avalidity period of the downlink data, so that the core network controlentity sets the first indication information that is further used toindicate the validity period of the downlink data, and deletes the firstindication information when the validity period of the downlink dataexpires.

Therefore, the server according to the embodiment of the presentinvention sends the first user equipment reachability notificationrequest message to the home subscriber server or the home locationregister, so that the home subscriber server or the home locationregister sends the second user equipment reachability notificationrequest message to the core network control entity, and therefore thecore network control entity sets the first indication informationaccording to the second user equipment reachability notification requestmessage, where the first indication information indicates that theserver buffers the downlink data to be sent to the user equipment, andthe server sends the downlink data to the user equipment when receivinga second user equipment reachability notification response message thatis sent by the home subscriber server or the home location registerafter the home subscriber server or the home location register receivesa first user equipment reachability notification response message thatis sent by the core network control entity according to the firstindication information; or sends the data buffering indicationinformation to the core network control entity, so that the core networkcontrol entity sets the first indication information according to thedata buffering indication information, where the data bufferingindication information indicates that the downlink data to be sent tothe user equipment is buffered and the first indication informationindicates that another entity has downlink data to be sent to the userequipment, and the another entity sends the downlink data to the userequipment when receiving a request message that is sent by the corenetwork control entity according to the first indication information andtriggers the downlink data, which can save power of the user equipment.

It should be understood that, features of the method embodiments of thepresent invention are applicable to the device embodiments of thepresent invention in appropriate cases, and vice versa.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraint conditions ofthe technical solutions. A person skilled in the art may use differentmethods to implement the described functions for each particularapplication, but it should not be considered that the implementationgoes beyond the scope of the present invention.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, reference may bemade to a corresponding process in the foregoing method embodiments, anddetails are not described herein again.

In the several embodiments provided in the present application, itshould be understood that the disclosed system, apparatus, and methodmay be implemented in other manners. For example, the describedapparatus embodiment is merely exemplary. For example, the unit divisionis merely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented through some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electronic, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. A part or all of the units may be selected according toactual needs to achieve the objectives of the solutions of theembodiments.

In addition, functional units in the embodiments of the presentinvention may be integrated into one processing unit, or each of theunits may exist alone physically, or two or more units are integratedinto one unit.

When the functions are implemented in the form of a software functionalunit and sold or used as an independent product, the functions may bestored in a computer-readable storage medium. Based on such anunderstanding, the technical solutions of the present inventionessentially, or the part contributing to the conventional art, or a partof the technical solutions may be implemented in a form of a softwareproduct. The software product is stored in a storage medium, andincludes several instructions for instructing a computer device (whichmay be a personal computer, a server, or a network device) to performall or a part of the steps of the methods described in the embodimentsof the present invention. The foregoing storage medium includes: anymedium that can store program code, such as a USB flash drive, aremovable hard disk, a read-only memory (ROM), a random access memory(RAM), a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific implementation manners ofthe present invention, but are not intended to limit the protectionscope of the present invention. Any variation or replacement readilyfigured out by a person skilled in the art within the technical scopedisclosed in the present invention shall fall within the protectionscope of the present invention. Therefore, the protection scope of thepresent invention shall be subject to the protection scope of theclaims.

What is claimed is:
 1. A method for transmitting data comprising:determining, by a core network control entity, after receiving a firstmessage sent by user equipment, whether first indication information isset, wherein the first indication information indicates that a serverbuffers downlink data to be sent to the user equipment, wherein thefirst indication information is associated with a validity period of thedownlink data, and wherein the first message is a tracking area update(TAU) message or a routing area update (RAU) message; and in response todetermining the first indication information is to be set in the corenetwork control entity, establishing, by the core network controlentity, a user plane bearer or a packet data protocol (PDP) context, andtriggering the server that buffers the downlink data to send thedownlink data to the user equipment through the user plane bearer or thePDP context, wherein establishing the user plane bearer comprises:establishing radio bearers between the user equipment and an eNodeB thatare associated with all activated bearers of the user equipment, andestablishing user plane connections between a serving gateway and theeNodeB that are associated with all activated bearers of the userequipment.
 2. The method according to claim 1, further comprising: whenthe validity period of the downlink data expires, deleting the firstindication information.
 3. The method according to claim 1, whereinestablishing the PDP context comprises: establishing radio bearersbetween the user equipment and a radio network controller (RNC) that areassociated with all activated PDP contexts of the user equipment; andestablishing user plane connections between the RNC and a servinggeneral packet radio service support node (SGSN) that are associatedwith all activated PDP contexts of the user equipment.
 4. The methodaccording to claim 1, wherein before determining whether the firstindication information is set, the method comprises: receiving a contextresponse message sent by a source core network control entity servingthe user equipment; and when the context response message comprises thefirst indication information, setting the first indication information.5. The method according to claim 1, wherein the core network controlentity comprises: a serving general packet radio service support node(SGSN) or a mobility management entity (MME).
 6. A non-transitorycomputer readable storage medium storing one or more programs, whereinthe one or more programs comprise an instruction, when executed by acore network control entity, the instruction enables the core networkcontrol entity to implement the following operations: after receiving afirst message sent by user equipment, determining whether firstindication information is set, wherein the first indication informationindicates that a server buffers downlink data to be sent to the userequipment, wherein the first indication information is associated with avalidity period of the downlink data, and wherein the first message is atracking area update (TAU) message or a routing area update (RAU)message; in response to determining the first indication information isto be set in the core network control entity, establishing a user planebearer or a packet data protocol (PDP) context; and triggering theserver that buffers the downlink data to send the downlink data to theuser equipment through the user plane bearer or the PDP context, whereinthe operation of establishing the user plane bearer comprises:establishing radio bearers between the user equipment and an eNodeB thatare associated with all activated bearers of the user equipment, andestablishing user plane connections between a serving gateway and theeNodeB that are associated with all activated bearers of the userequipment.
 7. The non-transitory computer readable medium according toclaim 6, wherein the operation of establishing the PDP contextcomprises: establishing radio bearers between the user equipment and aradio network controller (RNC) that are associated with all activatedPDP contexts of the user equipment, and establishing user planeconnections between the RNC and a serving general packet radio servicesupport node (SGSN) and that are associated with all activated PDPcontexts of the user equipment.
 8. The non-transitory computer readablemedium according to claim 6, wherein the operations further include:before determining whether the first indication information is set,receiving a context response message sent by the source core networkcontrol entity serving the user equipment; and when the context responsemessage comprises the first indication information, setting the firstindication information.
 9. The non-transitory computer readable mediumaccording to claim 6, wherein the operations further include: when thevalidity period of the downlink data expires, deleting the firstindication.
 10. The non-transitory computer readable medium according toclaim 6, wherein the core network control entity comprises: a servinggeneral packet radio service support node (SGSN) or a mobilitymanagement entity (MME).
 11. A core network control entity comprising: aprocessor; and a memory coupled to the processor, the memory havingprocessor-executable instructions stored thereon, which when executedcauses the processor to implement operations including: after receivinga first message sent by user equipment, determining whether firstindication information is set, wherein the first indication informationindicates that a server buffers downlink data to be sent to the userequipment, wherein the first indication information is associated with avalidity period of the downlink data, and wherein the first message is atracking area update (TAU) message or a routing area update (RAU)message; in response to determining the first indication information isto be set in the core network control entity, establishing a user planebearer or a packet data protocol (PDP) context; and triggering theserver that buffers the downlink data to send the downlink data to theuser equipment through the user plane bearer or the PDP context, whereinthe operation of establishing the user plane bearer comprises:establishing radio bearers between the user equipment and an eNodeB thatare associated with all activated bearers of the user equipment, andestablishing user plane connections between a serving gateway and theeNodeB that are associated with all activated bearers of the userequipment.
 12. The core network control entity according to claim 11,wherein the operation of establishing the PDP context comprises:establishing radio bearers between the user equipment and a radionetwork controller (RNC) that are associated with all activated PDPcontexts of the user equipment; and establishing user plane connectionsbetween a serving general packet radio service support nodes (SGSN) andthe RNC that are associated with all activated PDP contexts of the userequipment.
 13. The core network control entity according to claim 12,wherein the operations further include: when the validity period of thedownlink data expires, deleting the first indication.
 14. The corenetwork control entity according to claim 11, further comprising: aserving general packet radio service support node (SGSN) or a mobilitymanagement entity (MME).
 15. The core network control entity accordingto claim 11, wherein the operations further include: before determiningwhether the first indication information is set, receiving a contextresponse message sent by a source core network control entity servingthe user equipment; and when the context response message comprises thefirst indication information, setting the first indication information.